A Stargazing Program For Beginners - A Pocket Field Guide - 1st Edition (2015) PDF
A Stargazing Program For Beginners - A Pocket Field Guide - 1st Edition (2015) PDF
A Stargazing Program For Beginners - A Pocket Field Guide - 1st Edition (2015) PDF
Astronomers Pocket
Field Guide
A Stargazing Program
for Beginners
A Pocket Field Guide
Jamie Carter
A Stargazing
Program for
Beginners
A Pocket Field Guide
Jamie Carter
Cardiff, UK
ISSN 2198-0756
Astronomers Pocket Field Guide
ISBN 978-3-319-22071-0
DOI 10.1007/978-3-319-22072-7
ISSN 2198-0764
(electronic)
ISBN 978-3-319-22072-7
(eBook)
Preface
viii
Preface
orbit and seen the Universe in its entirety for the first time. In doing so you will
have learned how to visualize Earths astonishing journey around the Sun, and
you will have witnessed a tiny part of the Suns gradual journey through the
Milky Way.
If that all sounds like philosophy and geography more than hard science, it
should. Stargazing is too often associated with telescopes and astrophysics. So
critical is math in the modern approach to astronomy that the number of
humans who appreciate the night sky and its rhythms is dwindling. Its an
oxymoron: as public interest in the discoveries continues to increase, fewer and
fewer of us appreciate the night sky. Weve gained a lot of astronomical
knowledge, but weve lost the context.
This is not an astronomy book. Although it could act as a good grounding
in amateur astronomy, Ive tried to focus on gaining some cosmic perspective,
through stargazing, on the distances and scale of the night sky. To keep things
simple I have rounded up to the nearest light year and included only stars that
can be seen by the naked eye or when using only basic equipment. Theres
plenty of information included about forces at work in the night sky that you
cant see, but the focus is on visible stars, constellations, star clusters, galaxies,
and planets. Ive also used star names in place of astronomical designations,
which has often meant using Arabic names that have various phonetic spellings. The specific demarcations of the various constellations do change
depending on the books, apps, or star charts you use; Ive stuck with those
most familiar to me, and I make no apology either for taking the odd shortcut
or for including two asterisms of my own, Felis Major (Chap. 3) and the Baby
Giraffe (Chap. 6). Once youre familiar with the night sky youll begin to find
your own constellations, too. Thats what stargazers do.
As well as the vital constellations and clusters, and the weird and wonderful
nebulas, well also discover some dark sky destinations across the globe that
help increase knowledge and give a new perspective on familiar night sky
sights. Travel broadens the mind, and stargazing can be a journey in more ways
than one. By years end the reader will be able to glance at the night sky from
anywhere on the planet and tell in what direction theyre facing, where all the
planets are, and even where Galactic Center Point is. Now hows that for celestial geography?
While Ive included a mix of what I call flat and deep knowledge, theres an
emphasis on the latter. Star names, constellations, and the myths associated
with them all come from humans, and while theyre certainly interesting, they
tell us more about the human story than they do about whats really going on
up there. Its the science in the stars, not their fictional stories, that most
astounds. Deep truths about the distances of stars, their relation to one
another, and the rhythms of the cosmos will all be explored. You really can have
it all just while standing in your backyard.
The naked eye can go a long way in stargazing, but only so far. In this book,
we will use binoculars (from April) and telescopes (from September) because
theyre so useful for studying the sky and getting a deeper understanding.
Theyre optional, but for many stargazers, they prove irresistible. Were some of
the first people in existence to have both access to inexpensive binoculars and
Preface
ix
Jamie Carter
Acknowledgments
Thanks in writing this book primarily go to my wife Gill for her total support.
Spending hours standing in the dark, sometimes on freezing mountainsides at
13,000 feet, while I was looking for constellations and clusters is the definition of
going above and beyond. In addition to her photography and assistance in the
production of this manuscript, Gill also helped develop many of the star charts
and figures. The Felis Major asterism (Chap. 3) I found in the stars is for her.
The figures were created using the excellent Cartes du Ciel/Skychart
(www.ap-i.net/skychart/en/start) planetarium software, beloved by so many
amateur astronomers. The plush SkySafari (www.southernstars.com) planetarium software also proved invaluable for stargazing during the day and for fact
checking. Since SkySafari draws on the awesome Stars book and website (stars.
astro.illinois.edu/sow/sowlist.html) for its information, thanks also go to its
creator, Jim Kaler, Professor Emeritus of Astronomy, University of Illinois.
Thanks also go to Chris Bramley, Editor at the BBC Sky At Night magazine
(www.skyatnightmagazine.com), for giving me a reason to go in search of dark
skies, and to Stephen Tonkin, whose brilliant monthly Binocular Tour in the
same magazine first got me outside with a star chart.
There are those who have inspired and fueled my interest in the night sky,
not least those who have hosted me in the various dark sky destinations across
the globe that Ive been lucky enough to visit. Generosity, enthusiasm, and
valuable telescope time came from Jane Morgan at the Cosmos Centre and
Observatory (www.cosmoscentre.com) in Charleville, Queensland; Richard
Cooke at Stargazers Retreat (www.breconcottages.com/cottages/brecon/stargazers-retreat) in the Brecon Beacons, Wales; everyone at Lowell Observatory
(www.lowell.edu) in Flagstaff, Arizona; and the staff at Planetarium Cusco
(www.planetariumcusco.com) in Peru. I enjoyed stargazing with you all.
Thanks to Jrome Brun for driving me up the unfathomable road through the
clouds to Pic du Midi Observatory (www.picdumidi.com) and to HautesPyrnes (www.tourisme-hautes-pyrenees.com), Argels-gazost (argelesgazost.com), and Villa du Parc (www.lavilladuparc.fr) for their hospitality.
To the inspirational Christian Luginbuhl and Lance Diskan at Flagstaff
Dark Skies Coalition (www.flagstaffdarkskies.org): it was great talking to you
both. May the darkness you've worked so hard for always prevail in your precious town.
Chasing eclipses is an expensive hobby, so Im indebted to both Explorers
Astronomy Tours (astronomytours.co.uk) and Visit Faroes (www.visitfaroeislands.
com) for their incredible generosity in allowing me to stand dumbfounded
under the path of total solar eclipses in Queensland and the Faroe Islands in
November 2012 and March 2015, respectively. Invaluable help hunting the
xii
Acknowledgments
Contents
31
57
89
117
139
161
185
Part III
Deep Sky
209
10
231
11
255
12
279
305
14
325
15
351
xvi
Contents
Appendix
Stargazing Resources .........................................................................
407
409
Index ....................................................................................................
411
PART I
CHAPTER 1
How toStargaze
Let the night sky slowly sink in and it will always stay with you, wherever
you go, and whatever you do. Think about what it is youre about to do.
Going outside and getting confused wont get us anywhere, and with temperatures hovering around freezing at this time of year in much of the
northern hemisphere, its important to know what you want to achieve
and to do it as quickly as possible. January is a time for speed-stargazing.
The night sky takes an entire year to get to know; the stars you see tonight
will be in the same positions again exactly a year from now. Its huge, its
always moving, and it can seem complicated at first. All you can expect to
do in one stargazing sessionparticularly your first-ever attemptis to
see a single snapshot. Over the coming weeks and months these snapshots, sights, constellations and stars will become woven together in your
mind. Theyll get context, and their movements will begin to make sense.
Chapter 1
Fig. 1.1 The Big Dipper, also known as the Plough, one of the most recognized group of stars in the night sky. Credit: NASA
The stars arent going anywhere, so theres no rush; choose your battles,
keep warm, learn slowly, and repeat the stargazing activities in this book
again and again until they become second nature.
Where toStargaze
Theres no need to jump in the car and drive into the middle of the desert
(at least, not yet!). Find somewhere convenient, such as your own backyard,
the sidewalk out front, a local public park, a field or a beach. Try to choose
somewhere that doesnt have any lights in your field of view (street lights
and motion-sensing security lights are a stargazers biggest enemy).
Theres not much you can do about public lighting, but if a neighbor has a
bright, white security light, ask them nicely to turn it off. Its imperative that
you get away from direct lights that dazzle you. However, just as important
is that you have a clear view of as much of the sky as possible.
When toStargaze
Like all learning, stargazing is best done little and often. That way, the
things you learn will slowly sink in through repetition. In the beginning,
aim to stargaze just once or twice a week, for about 30minutes each.
Its technically possible to see a whole six months worth of night sky patterns if you stay up all night. Few of us have the time or the addictive personality to completely switch our body clocks and stay up all night
stargazing. Its not practical, which is why this bookand all stargazing
books, for that matterpresume that stargazing is done for a relatively
short time at about the same time each day.
Glimpsing at the night sky at 4:00a.m. can be quite exciting; what you see
is your stargazing sessions fast-forwarded, with constellations rising that
you otherwise wouldnt see for many weeks or months during the early
evening. However, for the sake of being practical, and for properly gaining
an understanding of how the night sky changes gradually each night as
Earth orbits the Sun, its best to stargaze at around the same time each
night; this book presumes 10:00p.m., which applies all year round, though
stargaze a few hours earlier in winter if you would rather.
In reality, clear skies will determine exactly when you get to do any stargazing. Clouds dont stick to a timetable. An hour or so after sunset when darkness has descended, go outside and look up at the sky. If all you see is
clouds, go back inside and watch TV, or read a book. Come back tomorrow.
That may seem like strange advice, but if youre going to be a stargazer,
youre always going to need a Plan B. Even if you can see a few stars
through gaps in the clouds, its better to postpone your debut as a stargazer; at the start of your career youre after the big wide-eyed, wide-angle
view of a clear sky.
Chapter 1
Fig. 1.2 A bright Moon can make stargazing very difficult. Jamie Carter
calendar with a diary and cross out an entire 10 days each month. If the
Moon is big and bright, it acts like a giant light polluter and leaves even
bright stars and constellations looking faint and washed-out (Fig. 1.2). Its
far more light polluting than any streetlight, or even a big city center, billboard or filling station, but it is very predictable. See Chap. 3 for more on
the Moons phases, how and when to best see it, and when best to avoid it.
Where toStand
A patch of grass or lawn is fine if its going to be a brief stargazing session
on a relatively warm night, but in January thats not likely. Stand on grass
for too long and your feet will soon turn to ice.
Dont plan on staying outside for too long to begin with. There is only so
much new knowledge one brain can take in, and after a while it resists. That
goes double if youre learning how to find shapes and patterns in stars you
dont recognize. Your neck will thank you for it!
Feet
Its always the feet that go first; the biggest reason for cutting short a stargazing session is cold feet, but this is easily avoided. There are many kinds
of socks that claim thermal properties, but one pair is never enough on a
cold winters night. Working on the principle that trapping warm air is the
best way to retain heat in your feet, a pair of thin socks (preferably merino
wool) worn under a pair of thick wool socks inside a pair of hiking boots
works best.
Legs
For stargazing sessions, legs are perhaps less important than your extremities, but its wise to wear a pair of thermal leggings under any pair of trousers, or double-layered thermal trousers. If later you decide to get a
telescope or develop a taste for astro-photography and consequently
spend more time outside (and more of it on your knees adjusting optics
and tripods in dewy conditions), a pair of waterproof over-trousers is a
must. If you can find some waterproof thermal trousers, even better
(ski pants are perfect).
Chapter 1
Core
Much more effective than one big jacket is using multiple layers for insulation, a tactic that is used by hill-walkers, hikers and survivalists. A wool or
technical base-layer wicks away moisture to keep you dry, which is essential to stay warm (avoid cotton, which gets wet with sweat and can leave
you freezing cold). Consider wearing a relatively thick long-sleeved baselayer, which hugely helps in preserving your core body temperature for
longer. Next on should be a warm fleece or wool jumper to trap body
heatpreferably with a hoodand then a down-jacket, which provides
both warmth and a basic waterproof layer. Find a jacket with pockets, since
youll always have some kind of stargazing paraphernalia with you; having
somewhere to easily stow a pen, notebook, flashlight, hat, gloves, lens
caps (and not forgetting your hands) is very useful.
Hands
What you wear on your hands entirely depends on what youre going to be
doing. When youre just starting out, youre likely to be consulting apps on
a phone and books like this one on a tablet (remember to turn the brightness down), so a pair of either fingerless gloves or touchscreen gloves
which let you swipe the screen of a smartphone or tabletare ideal. In the
depths of winter youll almost certainly need a pair of thermal gloves, too;
the warmest choice by far are a pair of mittens, which trap the warm air
around your fingers. If youre just going to be stargazing without books or
devices, either with the naked eye or with binoculars, then just a pair of
mittens is the ultimate choice. If you later opt for a telescope, then youll
begin a (likely life-long) search for the ultimate fingerless gloves.
Head
If your fleece layer has a hood, that might suffice. Better is a hat designed
for hikers that has flaps that cover the ears, especially if its windy. In the
depths of January, wearing a thermal hat with a double layering of fleece
is a good idea, though any kind of inexpensive woolly hat will do.
Neck
Forget binoculars or star charts; a tubular neck-scarf is the ultimate
stargazing accessory for any season. Positioned between fleece and hat,
they cover the gap where a chill wind can easily get in and sap your heat,
and ultimately your enthusiasm to stay outside. Balaclavas can be useful
for the same reasonthey often cover the neckbut if youve dressed well
then you may find that its just too much, and then overheating becomes a
problem.
Dont Forget
A pair of headphones can be useful if you plan to listen to music or a podcast while youre stargazing. Its useful to thread the cables of your headphones under the fleece layer before you finish dressing. In-ear models are
fine, but keep in mind that bulky over-ear models can double as earmuffs.
10
Chapter 1
Dipper will reveal themselves and soon become clearer. Faint stars will get
brighter after 10 minutes, and after 20 minutes youll see so much more
starlight, possibly more than youve ever seen.
DONT:
1. Look at your smartphone.
Its so tempting to put some music on, check something online, or even
use a planetarium app, but looking at a phones screen will destroy your
night vision (Fig. 1.3). Even if you do those things carefully with the
screens brightness turned down low, or use a red-light mode within a
specialist stargazing app (more on this in Chap. 2), theres a chance
someone will send you a message or call youand that bright call
screen can undo all of your good work in a second. Put your phone
away, or at the very least, stay in control of it by putting it in airplane
mode to prevent any calls.
2. Use your flashlight.
If its white, keep it out of sight! Reading anythingincluding a book,
planisphere or a star chartwith a white flashlight is a bad idea.
Flashlights need to be in red light mode, which is the only color of light
that dark-adapted eyes can withstand. If your flashlight cant go red,
consider buying a head-mounted flashlight that can (Fig.1.4); that way
you can read books, charts and maps with two hands. Though red light
modes tend to be subdued, flashlights increasingly use ever more
powerful and bright LEDs on normal white mode, so do be careful not to
switch back while stargazing. That goes double if youre stargazing with
someone else; a quick blast of 60 lumens in their eyes will make them
star-blind for 20minutes.
11
Fig. 1.3 Using a smartphone is the quickest way to lose your night vision.
Jamie Carter
3. Go back indoors.
Youve run out of coffee, you forgot to bring your stargazing manual, or
you just need to check the score of a big game on the TV. It can be tempting, but resist all urges to go back indoors, where white lights and LED
televisions will destroy your night vision.
12
Chapter 1
Fig. 1.4 A flashlight with a red light mode will help preserve your night
vision. Jamie Carter
nothing you can do about light pollution, but the sky glow from towns and
cities across the globe can actually work slightly in your favor. There are a lot
of stars up thereover 4000 from a dark sky sitewhich is a few too many
for the amateur stargazer to navigate. By blocking out faint stars and only
allowing the bright stars to shine through, some light pollution will make
your early forays into stargazingand particularly spotting constellations
slightly easier. Being underneath a blanket of stars is a great experience, of
course, but even experienced stargazers (most of whom live in cities) can get
disorientated if you put them in a truly dark place. So relax about light pollution; later on this year you can learn to hate it.
The Sun
Whats the Sun got to do with stargazing? While its tempting to ask you to
go into your backyard, lay on the ground and gaze up at the stars, in
January thats not practical. Instead, heres an easy question: whats the
13
brightest star in the sky? Its the Sun, of course; stargazing isnt an
exclusively nocturnal activity.
A Warning
Caution is needed here: never look directly at the Sun, and absolutely not
with cameras, binoculars or unguarded telescopes, as they magnify the
light and can cause injury and blindness. Partially blinded photographers
and amateur astronomers will attest to that; Ive even heard of one person
that, while attempting to watch the most majestic of stargazing events, a
total solar eclipse (Chap. 14), set fire to his shorts and his hair while using a
telescope!
14
Chapter 1
orbits it, and rotates as it does so, is key to appreciating the constantly
moving night sky. The stars appear to move precisely because Earth itself
is moving around one of them, and spinning as it does.
Celestial Geography
Its a big Universe out there, but theres a fact about the stars that few
know. All the stars you can see in the night sky with the naked eye are in
our Milky Waythey are our immediate neighbors. There are fewer visible
stars than you might think. On a clear night in a dark sky destination (at
least 40 miles from a city), about 4000 can be seen, though if you are in the
middle of a big city, its going to be more like 15 or 20.
15
in midnight sky, 6hours Universal Time (another term for Greenwich Mean
Time, which those in North America will be several hours behind). Star
charts also often have an index of major naked eye, binocular, and telescopic objects visible that month.
Using aPlanisphere
While star charts tend to be produced only for a single month, a planisphere can be used at any time of year. Inside the planisphere is a map of
every star and constellation viewable from the northern or southern
hemisphere during an entire year, but a moveable window in the top disc
only lets you see whats viewable on a specific date and at a specific time.
Simply adjust the upper disc according to the date and time shown
around the outside, and orient the entire planisphere so that the western
16
Chapter 1
Fig. 1.5 A star-chart for January 1 at 10 p.m., which will be accurate for
9p.m. mid-month and for 8p.m. by months end
and eastern horizons are in the correct place. Youll then have a map of
the sky above you, which you can adjust slightly an hour later to account
for the rotation of the Earth.
Although a planisphere is a great tool for understanding our seasonally
changing view of the northern hemisphere starsand I recommend you
get hold of oneby their very nature they cannot show you the position
of the planets. However, since theyre of much higher quality construction
than a paper star chart, the best planispheres often have a handy built-in
advantage for stargazing: they also glow in the dark!
17
18
Chapter 1
Fig. 1.6 The Big Dipper (also known as the Plough) is made-up of seven
stars or is that eight?
19
theyre actually moving across the night sky in the direction of the constellation of Sagittarius (Chap. 7), which is seen above the southern horizon in summer.
However, two of the Big Dippers starsAlkaid at the tip of the tale, and
Dubhe at the top of the bowlare not related to the others. Theyre also
both about 80 light years distant, but are moving away from the others.
Come back in 100,000years time and Alkaid and Dubhe will have shifted
to the right and the Big Dipper shape will be stretched and deformed.
Enjoy it while you can!
A Constant Constellation
But the best thing about the Big Dipper? If youre stargazing from the
northern hemisphere, its almost always present in the night sky, which
iswhy almost everyone knows about it. Its part of one of the circumpolar
constellations, which means that it moves around true north once every
24hours. An easy way to remember where the Big Dipper will be during
the year is the phrase spring up, fall down. In spring, the Big Dipper will be
above Polaris, and vice versa in fall.
The two most important stars in the Big Dipper for stargazing navigation
are Dubhe and Merak, the outermost two stars that make up the bowl
shape (Fig.1.6).
20
Chapter 1
Fig. 1.7 How to find Polaris using the Pointers in the Big Dipper
21
22
Chapter 1
Polaris is where the Earths axis is pointed towards, so it lies directly above
the north pole. Consequently, as the Earth rotates and the entire night sky
appears to move, Polaris is the only star that appears to remain still.
23
Fig. 1.8 The Big Dipper and Cassiopeia are always opposite each other in
the northern sky
24
Chapter 1
Looking East
Its time to look away from the circumpolar sights and look to the east and
south to some of the jewels of the January night sky. While everything weve
looked at so far can be seen at any time of the year, what were about to see
is fleeting, and visible for a shorter time. On this side of the sky the stars
appear to sweep from east to west if viewed constantly for a few hours, or
at exactly the same time on consecutive nights, but for how long youll see
individual stars will depend on where youre stargazing from. The exact
position of trees, your neighbors house or a hill may mean that you can see
specific stars and constellations for only a couple of months each year.
25
Fig. 1.9 How to locate Sirius, the brightest star in the sky
shortly. Place your outstretched fists, held together, on the left-hand side
of the belt of stars and orientated in the same direction, and the edge of
your left fist should just about reach a very bright star down towards the
horizon (Fig. 1.9). This is Sirius, also known as the Dog Star because its in
the constellation of Canis Major, the Great Dog.
Almost twice as big as our Sun, Sirius in the winter months is due south by
nightfall, though it never rises very high above the horizon. By summer,
Sirius is rising in the east just before sunrise. The long, hot dog days of
summer were blamed by the ancient Greeks on the Sirius-rise, which was
thought to give-off immense amounts of heat. In fact, Sirius has nothing
to do with the hot months of summer, but it underlines how important the
changing of the night sky has been in human history; the appearance of
stars indicates the passing of the seasons.
26
Chapter 1
Star or Planet?
When looking at the very brightest stars in the night sky, its very easy to
get confused by an interloper or twothe planets. Of course, the planets
can provide some of the greatest celestial sights any stargazer can see, but
really only with binoculars or a telescope, which well come to later in the
year. If you can see what you think is a bright star to the east, its probably
Jupiter. Since this giant planet orbits the Sun only every 12 years, its a
slow-moving presence in the same general area of sky for a year or so.
However, that doesnt mean its always visible; as Earth orbits the Sun, all
planets will appear to be behind it at some point during the year, and
therefore be impossible to see.
27
The Moon
Although many people learn to identify constellations like the Big Dipper
and Orion in their childhood, its the Moon thats frequently responsible for
stargazers fascination with the night sky.
28
Chapter 1
29
Fig. 1.11 The stars of Orions Belt are many hundreds of light years apart
30
Chapter 1
Fig. 1.12 The Moon rises about 50minutes earlier each day. Credit: NASA/
Goddard Space Flight Center Scientific Visualization Studio
the sky, how its lit (it may be a slim crescent, half-lit, or completely
illuminated), and how bright it is. Try to look at it at the same time of night
for three or four nights in a row and youll get a snapshot of how it moves
through the sky. Though it rises in the east and sets in the west just like
anything else in the night sky because of Earths rotation, the Moons
29.5-day orbit of Earth is going in the opposite direction. Consequently, it
appears to be in a slightly more easterly position in the night sky each
night. It sets 50minutes later in the west each night until it becomes Full,
before rising 50minutes later until its Newand thats its orbit complete.
References
Couper, Heather & Henbest, Nigel. Stargazing 2014. Philips, London. 2014.
31
CHAPTER 2
Sidewalk Stargazing
Stargazing is all about learning to recognize constellations, key stars and
phases of the Moon just by glancing up at the sky. When you see a star on
the horizon, youll be able to say, Thats Sirius, without a second thought.
Its actually very easy to do.
Even if your good intentions to stargaze get waylaid by social engagements
and the general business of life, there is a great way of reinforcing what
youve already learned. Whenever you find yourself outside in the hours of
darknessperhaps when youre walking through a city or in a parking lot
look up at the night sky and try to find one or two of the constellations
youve already learned. This can be quite tricky at first because you may be
Springer International Publishing Switzerland 2015
J. Carter, A Stargazing Program for Beginners, Astronomers Pocket
Field Guide, DOI 10.1007/978-3-319-22072-7_2
32
Chapter 2
33
Idle Stargazing
Repeating to yourself wow, look at all those stars! is not going to keep
you entertained for very long, which is why you need an observing list each
time your stargaze. Use the naked eye targets in this book as something to
aim for; if you can go outside for 25minutes and find a new constellation,
or perhaps two, thats a great session. Theres no need to rush. But heading
outside with no idea of what you want to achieve is a sure-fire way of losing
all enthusiasm, especially if its cold.
34
Chapter 2
Hands intheAir
Humans are built to scale. A tall person will have longer arms than a short
person. Their fingers and the size of their hands will also be of relative size.
The effect is simple: anyone can hold out an outstretched arm and make
simple measurements in the night sky using their just their fingers and
hands. Heres how (Table2.1).
35
5
10
20
Fig. 2.2 The Moon may appear large in the sky, but its possible to cover it
completely with an outstretched finger-tip. Credit: NASA
36
Chapter 2
of a finger. It is only by chance that the Sun appears to be the same size in
the sky as the Moon. Though the Sun is 400 times bigger than the Moon,
its also 400 times further away, which is why we can experience a total
solar eclipse (Chap. 14).
Now try to measure how many degrees above the horizon the Moon is
using your hands. The presence of mountains or buildings might mean you
have to make an educated guess as to where exactly the horizon is, but
youll get a result thats accurate enough.
37
There are seven stars that make up the six points of the Winter Circle, most
of which are relatively close neighbors of our Sun. Begin at Sirius, the lowest star of the asterism, and rising in the south, then move clock-wise. Use
your fists to check that youve arrived at the right constituent star until you
return to Sirius.
38
Chapter 2
Fig. 2.3 The huge Winter Circle asterism groups together the brightest,
most dominant stars of the season. Numbers in red refer to how many outstretched fists can be placed between each star.
39
Table 2.2 The distance from Earth of the Winter Circle stars
Sirius in Canis Major
Rigel in Orion
Aldebaran in Taurus
Capella in Auriga
Castor and Pollux in Gemini
Procyon in Canis Minor
positions as they really are. While its difficult to consider distances of multiple stars at once, theres an easy way to get an impression of depth in the
night sky: find the interloper. In this case, its Rigel at 800 light years. Later
in the year well look at the Winter Circle once again, but instead of distance, well think about the ages of the stars (Chap. 12).
40
Chapter 2
light from millions of distant stars begins to become visible. By April the
Winter Circle is sinking in the west at dusk and the Milky Way is lost in the
haze of the horizon, but theres much more to see come summer (Chap. 7).
Serene Stargazing
Dont get stressed about the stars. The downside of stargazing in winter is
that you may not have a clear night for weeks on end. Considering the clarity of the stars during January, bad weather can be incredibly frustrating,
but perhaps coping with disappointment is part of why stargazing is said
to be good for your temperament.
Stargazing is a hobby thats entirely weather-dependent, and its best to
stick to properly clear nights. Although it is possible to spot individual
stars, planets and the Moon between the clouds, the real wonder of
stargazingespecially at the beginningis the wide-eyed view of the
cosmos that you can only really get under totally clear skies.
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Fig. 2.4 Star-hopping from Orion through Taurus to the Hyades and the
Pleiades
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Fig. 2.5 The Pleiades (M45) in Taurus is a spectacular naked eye star cluster.
Credit: ESO/S.Brunier
43
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45
Fig. 2.6 The Winter Triangle includes bright stars Sirius, Procyon and
Betelgeuse
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to go supernova. Massive stars burn up their fuel much faster than smaller
stars (such as our Sun), and as the core collapses, theres a huge explosion.
Betelgeuse could go supernova at any time, though its at such a distance
that it may have already happened; as it is 642 light years from us, it could
have exploded 642 years ago. If thats the case, it will look like its going
supernova any minute now though it could just as easily take a million
years.
642
800
260
1425
550
7500
December-April
December-April (Fig.2.4)
April-June (see Chap. 4)
May-December (see Chap. 6)
May-July (see Chap. 7)
Only visible from the southern
hemisphere (see Chap. 13)
http://www.nasa.gov/topics/earth/features/2012-supernova.html
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Sizing-up theCircle
Stars change color depending on their temperature, which in turn depends
on their mass. The most massive, hottest stars are blue. The archetypal blue
supergiant is Rigel. The coolest are orange, such as Betelgeuse (Chap. 2)
and Antares in Scorpius (Chap. 7). Those in between are yellow; our Sun
falls into this category (Chap. 8).
Betelgeuse and Rigel might be on the verge of destruction because of their
massive size, but the other stars in the Winter Circle (Fig. 2.3) region are
hardly small. In fact, there's not a single star among the seven that is as
small as our Sun. Sirius, Procyon, Castor and Pollux are all around twice the
diameter of the Sun, while Capella is 10 times the size, Aldebaran 44 times
the size and Rigel a massive 70 times the size.
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http://www.cfht.hawaii.edu/en/news/Orion/
49
grows older, star birth will lessen and it will begin to resemble a tight
cluster like the Pleiades. Its stars will then spread out, as has happened
with the much older Hyades. Eventually, the stars born in the Orion Nebula
will disperse completely and drift, apparently alone, in the cosmos. Our
Sun is at that stage now; its origins are hidden from us. All stars come from
clusters, and before that, from a nebula. So when you stargaze at the Orion
Nebula, youre looking at a place very similar to where the Sun was born.
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Deep Time
Though time isnt as difficult to express as distance, the night sky operates
on a time-scale thats hard to comprehend. Astronomers using powerful
telescopes like the Hubble Space Telescope (see Chap. 12) can look back
into deep time by capturing images of galaxies over 13 billion light years
away, which is only a few hundred million light years after the Big Bang
created the Universe. Are those galaxies actually still there? Its impossible
to knowthey could have only lasted a few million yearsbut their light
is only now reaching us. If that kind of scale is just unfathomable, try this
one; the light from the Andromeda galaxy, which is best viewed in October
(more on this in Chap. 10), was produced 2.5 million years ago as the first,
distant ancestors of humans were beginning to use tools in Africa. Yet this
is merely the galaxy next door; in the Universe just as within our own galaxy, distance and time are intertwined.
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Age
Universe
Milky Way galaxy
Andromeda galaxy
Sun
Earth
The Pleiades
Orion Nebula
Human species
Stargazing Apps
Like everything to do with smartphones and tablets, the temptation of
having an instant stargazing guide is hard to resist. Not only are many of
these apps free, but these augmented reality planetarium apps will tell you
exactly where various stars, constellations and planets are. Wheres Sirius?
Whats that star near the horizon? Are there any planets in the night sky
tonight? With a little help from your smartphone, these and other questions become easy to answer as you find your bearings and transform your
understanding of Earths ever-changing view of the solar system and
beyond. Hold your phone up to the sky and your smartphones compass
and accelerometer will present a live view of exactly whats in front of you.
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So whats the catch? Finding something only on your phones screen means
nothing. Successful stargazing is finding most of the major constellations
in the sky at any time of the night or year without any technology to help
you, and to know whats due to rise soon.
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www.google.co.uk/mobile/skymap
http://www.icandiapps.com/icandiapps/night-sky-apps/
5
http://vitotechnology.com/sky-live.html
4
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The makers of Sky Live also produce Star Walk,6 which has a database of over
200,000 stars, planets, constellations, satellites and galaxies in the night sky.
Navigating the night sky is easy because it tracks as you move your phone.
Its also possible to interrupt it by pinching to zoom in, or dragging it to easily
study a specific area of sky. Its also got a search box; enter the star or object
youre looking for and it puts an arrow on the screen that points you in its
direction until youve turned to face it. All this can be done in a red-light
night-vision mode. Just as professional and available as both a smartphone
app and as software for a desktop computer is SkySafari,7 which also has a
night mode. Most stargazers laptops will have one of the free planetarium
programs, too, such as Stellarium8 or Cartes du Ciel,9 which allow you to navigate the night sky, rewind and fast forward it, build observation lists, and
print out star charts. As you get more experienced, theyre invaluable, but
dont make the mistake of spending hours learning how to use a new piece
of software when you should be outside learning about the night sky.
Swapping Hemispheres
If you want to study the southern hemisphere stars (Chap. 13) without
travelling, just point one of these apps at your feet. It sounds dumb, but it
does help you see how restricted your view of the night sky always is.
Stargazing can be done any time, anywhere, but its best done in as wide a
variety of places as possible. Although theres plenty of overlap in terms of
stars and constellations, swapping hemispheres can be disorientating, and
this when stargazing apps really come into their own.
However, anyone who has crossed the equator and tried to use one of
these apps will know that they can go wrong. Some apps travel better than
others; while they might work fine in your backyard, if you swap hemispheres (perhaps by going on vacation to Australia, South America or
southern Africa) these apps often present the wrong horizon when you
hold your phone up to the sky, which can be very confusing. Its often
http://vitotechnology.com/star-walk-2-guide-sky-night-day.html
http://skysafariastronomy.com/products/index.html
8
www.stellarium.org
9
www.ap-i.net/skychart/en/start
7
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necessary to restart your phone, and perhaps even delete and re-download the app, until it gets an accurate fix on where you are. (This is best
done over WiFi before you travel into remote areas.
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bright to look at, leaving stargazers dazzled and washing out all but the
brightest of stars. Its best avoided, especially if youre headed for dark
rural skies to stargaze. However annoying moonlight may be for stargazing, the sight of a Full Moon rising and setting is one of natures greatest
and least observed spectacles (more on this in Chap. 8).
References
SPACE.com Staff. 100 Billion Alien Planets Fill Our Milky Way Galaxy. [ONLINE]
Available at: http://www.space.com. 2015. [Accessed 01 June 15].
Temming, Maria. How many galaxies are there in the universe? [ONLINE]
Available at: http://www.skyandtelescope.com. [Accessed 01 June 15]. 2014.
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The Ecliptic
Its possible to see the plane of the solar system on every single clear night.
On almost the exact line that the Sun appears to cross the sky during the
day, so too the planets cross by night. This imaginary line is called the ecliptic, and it stretches from the point on the eastern horizon where the sun
rises to that place where it sets in the west (Fig. 3.1). Its hereand only
herethat youll see planets during darkness. Exactly how high in the sky
the ecliptic is depends on the time of year; since Earths axis inclined by
23.5, it appears to move with the seasons.
Fig. 3.1 Star-chart for March 1 at 10p.m., with the ecliptic marked; the Sun
and the outer planets appear to follow this line across the sky
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The knowledge that the Suns path across the sky is exactly the same as the
Moon and the planets is simple, but will change your night sky navigation
forever.
Astronomers arent sure why planets orbit the Sun in the same, flat plane,
but it could be to do with how the dust cloud that collapsed to form our
Sun was rotating. The result was a flattened disk of dust, from which all the
planets formed (Odenwald 1998).
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Spring Constellations
March brings with it new constellations and celestial wonders. The sparkling stars of winter begin their dive down to the horizon just after sunset,
and we bid farewell to Taurus, the Pleiades and Orion. This month we will
find the constellation of Bootes rising in the east, but there is still time to
get acquainted with the winter stars in the constellations of Auriga, Gemini
and Canis Minor.
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Fig. 3.2 Arc to Arcturus: an easy way of finding this orange star in spring
and summer is from the Big Dipper
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Fig. 3.3 The constellation of Auriga includes three star clusters and a tiny
triangular asterism called The Kids
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Fig. 3.5 Canis Major and the authors own constellation of Felis Major
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created Vela (the sail), Pyxis (the compass), Puppis (the stern), and Carina
(the keel). Gould had worked for the US Coast Survey (Encyclopedia
Britannica 2015), so also had boats and navigation on the brain.
If constellations were created from scratch now, they would probably not
be named after gods, hunters, mythical animals and queens. Modern
humans would likely find the shapes of familiar, everyday obsessions in the
night sky, such as smartphones, aircraft, trains and cats (see above).
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progresses. Just as the Sun appears to move across stars, rendering them
invisible to us, once its passed over them those same stars become visible
just before dawn. To stargaze is to witness the awesome clockwork of
Earths orbit around the Sun.
This month and next, have a look for the Pleiades just after sunset before it
gets lost in the haze during May. Unless youre up well before dawn this
summer, well see the Pleiades again in November (Chap. 11) when it
announces the coming of Orion and the Winter Circle (Chap. 2).
Celestial Motion
The entire sky appears to shift forwards by fourminutes each night. If you
see Arcturus rise at 19:12 on March 15, it will rise at 19:08 the following day.
Six months later, it will rise at 07:12in the morning on September 15 (not
allowing for daylight saving changes). If stars are rising fourminutes earlier
each night, it follows that theyre always taking only 23hours and 56minutes
to return to where they were the previous night. This is what astronomers
call a sidereal (pronounced sid or side-ear-real) day.
Since everything shifts forwards by four minutes each day, star-charts
move backwards. Four minutes may not seem like much of a difference,
and you most likely wont notice it if you spend a few consecutive nights
stargazing, but over the course of a month those daily four-minutes
changes add up to about twohours. Thats why most star-charts are accurate only for a two-hour window (Chap. 1) that gradually shifts backwards.
The star-charts at the start of all of the chapters in this book work for
10 p.m. at the beginning of the month, and for 8 p.m. at the end of the
month.
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Understanding theEquinox
The vernal equinox happens in late March and heralds the start of
spring. You may think it has little to do with stargazing, but understanding the equinoxwhich merely means equal nightwill help you put
the seasonal changes in the night sky into a bigger context. Along with
the fall or autumnal equinox in September (Chap. 9), it marks the point
when the midday sun is directly above the equator, giving every location on the planet 12hours of daylight and 12hours of darkness. It also
signifies the moment when the ecliptic crosses the celestial equator.
Only on those twodays of the year will the Sun rise exactly east, follow
an arc right along the celestial equator, and set in the exact west direction (Strobel 2015).
The vernal equinox is also when the north pole at last sees some twilight after
six months of darkness; between the equinoxes, the 23.5 tilt of Earth means
that the Sun and, hence, the ecliptic, slips further north in summer. The maximum point is marked by the summer solstice (Chap. 6), which means the
longest day, and therefore limited, but warm stargazing. After the fall equinox, the Sun appears to move further south, culminating in the winter solstice
(Chap. 12), which means long, cold and clear nights for wrapping up warm
and going outside with a star-chart.
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eyes that are dark-adapted should be able to find them even in lightpolluted skies. Some cultures think it looks like a skunk (Chap. 15).
Fig. 3.6 The huge constellation of Ursa Major contains the Big Dipper
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Fig. 3.7 The constellation of Leo hangs above the Realm of the Galaxies
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These will give you advance warning on when you can witness a planet at
opposition, which is when Earth is between the Sun and a planet, so at its
closest and brightest. Or a maximum elongation, when Venus or Mercury
appear to be at their furthest distance from the Sun, and so more easily
visible after sunset. Also when solar and lunar eclipses are going to occur.
Dont rely on the mainstream media to highlight interesting celestial phenomena. Journalists often get excited about comets, asteroids coming
anywhere near Earth, and perhaps the odd meteor shower, but that's about
it. You need to arm yourself with some reliable stargazing news sources.
Useful Websites
If you dont want to miss anything, then several websites are on hand; the
astronomical calendar at www.in-the-sky.org is useful because it tailors a
diary not only to your exact location, but also shows you only those events
that you will be able to see. For instance, choose naked eye only and it will
give you the phases of the Moon, meteor showers and eclipses, but change
that to visible thorough a four-inch telescope and youll also get details of
various galaxies, star clusters and the more distant planets. The Sea & Sky1
website is great for inspecting upcoming celestial events, too, though my
personal favorite is the slick and simple EarthSky,2 which emails a daily
update that includes details of what to look for in the northern hemisphere
night sky tonight, photos of yesterdays significant celestial event (perhaps
a close conjunction of Venus and the New Moon) and other science news.
Its also worth putting search terms like top 10 astronomical events into a
search engine at the beginning of every year to find articles on the upcoming eclipses, meteor showers, conjunctions and perhaps even comet sightings that you absolutely need to know about in advance. Why do you need
to know? Because no-one wants to be flying home from their annual holiday during a total solar eclipse, ormuch more likelyaccidentally planning a road-trip through, or a vacation in, dark rural skies during Full Moon
week when the stars are all but obliterated. That would be a huge shame. In
stargazing, planning is everything, so put anything that might be relevant
to you in your diary or calendar.
1
2
www.seasky.org
www.earthsky.org
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Coping withDisappointment
Just as important as knowing exactly whats going to be happening in the
night sky later on that day is being relaxed enough not to get too annoyed
when the inevitable clouds drift over to ruin the chance of observing something potentially very special. I recently traveled to the Faroe Islands in the
North Atlantic to witness a total solar eclipse. All but a handful of the
8000+ eclipse-chasers (Chap. 14) who had traveled across the globe to be
there saw nothing. Thats just the way it goes with stargazing and astrotravel, so it's best to cultivate a relaxed attitude towards the weather and
always have a Plan B.
How toBeanOutsider
Night vision takes time to cultivate and only second to destroy. Theres nothing worse than heading outside in your winter coat and spending 20minutes dark-adapting your eyes before realizing that youve left your torch/
binoculars/sky chart/house keys inside. There are many other faux pas that
practiced stargazers try to avoid. Heres a few things to remember:
Clear theArea
Take down the clothes-line in your backyard and put the lawnmower
awayboth are stargazing hazards. Ditto chairs and other garden furniture, though a table can be handy for storing equipment such as books,
drinks and binoculars.
Switch-off theLights
Light pollution in your own backyard is easily avoided, if its coming from
the back of your house. If youve got a motion-sensing light, deactivate it.
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Stargazing Uniform
Stargazing can come with a lot of paraphernaliaespecially in winter
and instead of assembling it all each night, it can be useful to have a coat,
scarf and hat ready to put on quickly.
Pen andPaper
Always take something for noting down objects, questions or notes to
research later. Some stargazers like to keep an observing diary, too, to keep
track of what theyve seen, when, and in what conditions. Waterproof notebooks can be useful for protecting against dew.
Phases oftheMoon
The Moon is always half lit by the sun, but from the surface of the Earth, it
doesnt look that way. This is just as well for stargazing; as the Moon orbits
the Earth, the visible sunlight it reflects waxes and wanes. Slowly throughout the month the crescent Moon will wax towards a Full Moon as it gets
further from the Sun, then wane back towards a crescent Moon as it gets
closer. Moon-watchers have divided up the Moons 29 day orbit into eight
distinct phases (Fig. 3.8), each lasting for about 3.5days, and each with a
rather confusing name. Knowing where the Moon is in its cycle is allimportant for stargazers.
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Waxing Crescent
For the first few days after the New Moon, a slowly increasing crescent Moon
can be seen in the western sky just after sunset and just before sunrise. Try
to catch it a few hours after its New phase and youll see the arresting sight
of a very slight slither of a crescent Moon. Since its still in the general direction of the Sun, its during these first few days that youre most likely to see a
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crescent Moon accompanied by Venus, and possibly Mercury, too (Chap. 11).
This is also a great time to study features on the right-hand side of the Moon,
as seen from the northern hemisphere (Chap. 11).
Waxing Gibbous
If the word crescent to describe the Moons illumination is descriptive,
youre less likely to have come across gibbous. Also known as egg phase to
stargazers, a Waxing Gibbous Moon describes the phase from half-lit to
Full. The terminator, the line that separates the lit and un-lit parts of the
Moon, begins to bulge-out to the east. Stargazing begins to become difficult as the Moons increasing light washes-out the sky, and it sets in the
small hours, well after midnight.
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Waning Gibbous
With this phase, the night skys chief light polluter drastically drops in
brightness. Its another egg phase, which is something of a relief not only
because the Moon is less illuminated, but because it rises later. During this
phase the Moon rises about 9p.m. and beyond. At this time of the Moons
orbit, its still very bright and can interfere with stargazing, but conditions
are about to drastically improve.
Waning Crescent
Another daytime Moon view is the Waning Crescent, which sees the illuminated Moon shrink to back to new. By this time the Moon is rising at 3a.m.
and setting before sunset, so its not a Moon most stargazers often see. Is it
worth getting up early to see a Moon that looks very similar to the much
more conveniently-timed Waxing Crescent two weeks previously?
When toMoon-gaze
Definitely in the first week after a New Moon, which is its Waxing Crescent
and First Quarter phases. As well as it not being as bright and dazzling as
during the following Waxing Gibbous and Full phases, its also visible at a
sensible time of night if you stargaze before bed.
The rule of thumb is this; if its a good night for stargazing, it might also be
a good night for Moon-viewing. The exception is after the Full phase, when
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Fig. 3.9 Earthshine is visible a day or so before and after New Moon. Credit:
ESO/Y.Beletsky
the Moon rises later and later; the Moon's Third Quarter and Waning
Crescent phases are not seen by many stargazers since they dont rise until
the small hours. The Moon in these latter stages of its orbit becomes a predawn object for early-risers only (Fig.3.9).
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area is, for the only time all month, small enough for your eye to see both.
As the Moon becomes more brightly lit, your eyes become overwhelmed
by the glare and can no longer see Earthshine.
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Its tempting to use binoculars and a telescope, and theres no reason not
to, but always be aware of the wide-eyed view. People see photographs all
the time of the beautiful things that are accessible by telescopes, and to
some level instrumentation can help you see some of that, says Chris. You
can look at clusters and planets through telescopes, and thats moving to a
lot of people, but the immediacy of just using your eyes is so valuable. The
real connection is made when you get the whole panorama of the overhead sky with its thousands of stars. The light that you see is really from
those stars, trillions of miles away, emitted hundreds, thousands or even
millions of years agonot from a computer screen or a page. Above all
stargazing is about making a connection with the Universe as it really is.
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References
Dunlop, Storm. Night Sky: Get to Know the Natural World. HarperCollins,
London. 2004.
Encyclopedia Britannica. Sextans & Benjamin Apthorp Gould. [ONLINE] Available at: http://www.britannica.com [Accessed 01 June 15]. 2015.
Odenwald, Sten F.The astronomy cafe: 365 questions and answers from ask the
astronomer. Palgrave Macmillan, USA. 1998.
Sessions, Larry & Byrd, Deborah. Arcturus cuts through galaxys disk. [ONLINE]
Available at: http://earthsky.org [Accessed 01 June 15]. 2015.
Strobel, Nick/Astronomy Notes. Motion of Our Star the Sun. [ONLINE] Available
at: http://www.astronomynotes.com [Accessed 01 June 15]. 2015.
PART II
A CLOSER LOOK
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1
Technically its possible to see 500010,000 stars with the naked eye, but only under
perfect conditions. From most backyards its nothing like those figures.
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Star-hop toSpica
Weve already seen the constellation of Bootes (Chap. 3), going Arc to
Arcturus from the tail of the Big Dipper. However, the rest of that memory
aid is revealed this month as the bright star Spicaessentially a summer
starappears above the horizon, replacing the sinking Sirius.
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Fig. 4.2 Arc to Arcturus & Spike to Spica is a spring signpost, but also look
out for the Spring Diamond asterism
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The Lyrids
A shooting star is a meteor hitting the Earths atmosphere and burning up,
and youve probably already seen dozens of them. They happen regularly
enough for a stargazer to see them frequently any time of year, but meteor
showers are predictable. One such meteor shower is the Lyrids, which happens in mid-April as Earths orbit takes it into the dust and debris left over
from a comets passing (Comet Thatcher, which last visited the solar system
back in 1861 and wont return until 2276!). It gives stargazers a small
chance of seeing some seriously good shooting stars. Its one of the oldest,
so not the best meteor shower of the year, with about 20 meteors per hour
normal. But what the Lyrids lack in quantity they can make up for in quality; watch out for bright fireball trails behind the occasional shooting star,
which can last a few seconds. A stunning sight!
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A New Layer
It's time for a closer look. A pair of binoculars will help us look deeper into
the constellations and the night sky around them. Why not a telescope?
Well, well get to a telescope eventually (Chap. 9), but binoculars have four
huge advantages over a telescope at this stage (and, indeed, any stage) of
your stargazing career. Firstly, theyre portable, which means you can easily
take them on vacation as well as just leaving them in your vehicle or your
luggage. Secondly, binoculars will give you an upright, stereo view of the
heavens, unlike the one-eyed view through a telescope. Thirdly, youll get a
far wider field of view than through a telescope, which is ideal for looking at
objects of a certain size. For instance, the stars of the Pleiades look stunning
in a pair of binoculars, but far less so in a telescope. Lastly, binoculars are
much easier to aim and focus than a telescope. If youre more interested in
stargazing than gadget-gazing, binoculars are what you need.
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Choosing Binoculars
Stay handheld and highly portable. At this stage you dont need to buy a
special pair of binoculars designated only for astronomy. There are various
antireflection lens coatings that can increase the brightness and improve the
sharpness of the images, but neither are particularly important at this stage.
You may already own a pair of binoculars that will do just fine, though its
likely youll want to upsize slightly. Before we consider sizes, you should
know that buying binoculars is all about marrying up magnification and
brightness. The first number in the specification for a pair of binoculars
denotes the magnification (or power), while the second number describes
the aperture. So, a pair of 7 50 binoculars offers you an image that is
seven times bigger than what you would see with your naked eye. The
second number, 50, is the diameter in millimeters of the objective lens,
which is the optics on the front of your binoculars. This is simply about how
much light is gathered, and so how bright the image can be.
Any pair of binoculars with over 10 magnification is almost impossible to
hold steady enough without a tripod to make out detail. Its best to go into
the store and try out some binoculars yourself, but as a rule of thumb a pair
of binoculars with the ratings of 7 50, 10 42 or 10 50 will do just fine,
and shouldnt cost you more than about $100$150. However, there are a
few other things to think about: since youll be outdoors, a waterproof
design makes a lot of sense. The more compact and lightweight they are,
the better if you plan to travel with them because they will need to go in
your carry-on baggage. Lastly, try to find a pair with twist-up eyecups,
which are easier to look through and help block ambient light.
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Advice on when and why to buy bigger binoculars, how to use them, and
why they can be worth the hassle will come later (Chap. 12). For now, 7 50,
10 42 or 10 50 are more than enough; I guarantee youll use them more
than any telescope you buy at this stage.
First Light
Stargazing and astronomy on every level is about light, so when a brand new
telescope gets used for the first time, its called first light. To get you started with
your new optics, here are five sparkling sights that look best in binoculars.
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the focus ring back and forth until you get a sharp image in your left eye.
Now close your left eye and open your right eye, and adjust the diopter
ring (which is usually found on the right eyepiece) until your right eye sees
a clear image. Its this second step with the diopter ring that most people
ignore, but it can make a big difference, because the binoculars are now
calibrated to your specific vision.
How much of the night sky youll see in your binocularsthe field of view
depends on the specifications; 7 or 10 binoculars will show you, on average, around eight degrees of sky.
Fig. 4.3 The Pleiades through binoculars displays hundreds of stars. Credit:
NASA, ESA, AURA/Caltech, Palomar Observatory
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at the center of the Pleiades, we would see nine bright stars in the sky at
least as bright as Venus is in our night sky (Consolmagno and Davis 2011).
Be sure to observe the Pleiades this month as it will soon be gone until
November.
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Fig. 4.4 The Orion Nebula (M42), is in the middle or Orions Sword, with the
three Belt stars to the upper-right. Credit: ESO/S.Brunier
Reducing Image-Shake
Image-shake is a big problem that is easy to reduce. If the image in the binoculars is trembling and blurred (it probably will be), prop-up your elbows on
your chest to keep your arms steady. However, this only works well if youre
aiming the binoculars fairly close to the horizon. Cures for image-shake are
myriad; leaning against a wall, place your binoculars on top of a fence or railing, or use an upturned broom to support them. Image shake gets worse as
your arms get tired, but you can easily lessen that if you lay down on the
ground or sit on a chair. Similarly, if you get into the habit of sitting while you
use binoculars (though you will have to lean back a lot) you can eliminate
80% of the neck ache that most binocular-wielding stargazers experience.
However, the most important thing to remember is to decide what you
want to look at before you point your binoculars at the night sky. Theres a
lot of stars out there, and just idly sweeping your binoculars across the sky
is likely to leave you lost, frustrated, and with tired arms and a shaky image.
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Fig. 4.5 Perseus and the Double Cluster, two separate open clusters each
containing hundreds of stars
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Fig. 4.6 Sirius, Canis Major and four open clusters nearby, including M41
just below
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stars, which are around 2300 light years distant. This open cluster is most easily
found in dark skies, which is so often the case with anything less than 10 above
the horizon, though M41 is bright in binoculars. There are numerous other open
clusters nearby, including M46, M47 and M50.
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Sister Clusters
Open clusters are great targets for binoculars, and there are plenty to look
at in April. Some fill the field of view in binoculars, while others are small,
misty patches that can only be glimpsed. Star clusters contain stars of a
common origin, but theres more to that story. Though they may be visible
on different sides of the sky, seemingly separate star clusters can themselves share a common origin.
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Fig. 4.7 The Beehive Cluster in Cancer can be found roughly halfway
between Pollux in Gemini and Regulus in Leo
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A Common Origin
Though theyre significantly separated in the night sky both in position and
light years, the Hyades and the Beehive Cluster probably have a deep connection. Despite the stars of the Beehive being much further from us than
those of the Hyades, both clusters are of a similar age and size. Whats more,
astronomers have studied their motion across the Milky Way and measured
them to be very similar (Rees 2011). Rewind their motion, and both the
Hyades and the Beehive appear to come from the same stellar nursery in
the Milky Way, somewhere much like the Orion Nebula (See Chap. 2).
Written intheStars
The night sky defies any efforts to catalogue it in any meaningful way.
However, that hasnt stopped people trying. The stars have had endless stories attached to them, with constellations created, studied and written about
by myriad cultures. Stars have been catalogued by astronomers multiple
times, some creating their own naming conventions and others happy to use
existing norms. The end result is a bit of a mess and impenetrable to the
casual stargazer, but there are some general rules that make it easier to wade
through the Greek, Latin and Arabic, and the seemingly random naming
conventions that attempt to put the night sky into some kind of order.
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other stars and objects just because theyre in the same general direction
from Earth? Imagine if you could see, through your upstairs bathroom window, a huge city in the far distance that youd never been to, and which was
slightly illuminated at night. Now imagine calling it Alpha Bathroom Window.
A crazy idea? Perhaps, but thats the system we use.
Stargaze enough and read around the subject and youll get past the baffling naming conventions and get a proper appreciation of what youre
actually looking at.
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Need toKnow
Stargazing isnt all about these conventions and numbers. In fact, its better
to ignore them since they can be misleading. What these naming conventions all have in common is that theyre designed by, and for, succeeding
generations of astronomers using different optics over hundreds of years.
Should there be a much simpler, but more comprehensive system solely for
stargazers? I dont think so. Some sights are better with the naked eye, others in binoculars and many more are only visible through telescopes. There
are also vast differences in both the equipment being used now as well as
ever-rising levels of light pollution. Its therefore likely that any attempt to
re-catalogue the night sky would just add more bureaucracy.
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isnt on its own; as well as being part of a constellation in its own right, this
month it is encircled from below by one of the largest constellations of all,
Draco (pronounced dray-ko) the Dragon.
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Fig. 4.8 Ursa Minor, the Guardians, the Engagement Ring and the huge
constellation of Draco, which is easiest to find during April
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star above the north-eastern horizon. Thats Vega (Chap. 5). Draco curves in
a backwards S-shape between the two. Dracos head is just above Vega;
bright stars Etamin and Rastaban are joined by two others. Move west until
youre under Polaris, go half-way back to Bootes, then curl around Ursa
Minor, adjacent to the Big Dipper (Fig.4.8).
Do WeNeed Constellations?
Its easy to get caught-up in the constellations, but the shapes they make
are largely make-believe memory aids. Astronomy tells us that few stars in
the major constellations are close companions. The patterns they appear
to make are a product of little more than line-of-sight (such as Orions Belt,
Chap. 1) that can only be visualized from our viewpoint in the Milky Way. If
thats the case, do constellations still matter?
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real story of the stars is universal in the literal sense; its about the miraculous
scale and power of nature, a true story that were only just begining to
unravel. Who cares about Greek mythology?
So we should forgetall about the constellations, right?
Myths andMethod
There are many myths and legends linked to constellations that are useful
to understand; Greek mythology has Scorpius (Chap. 7) and Orion as mortal enemies so puts them on opposite sides of the sky, with one rising as
the other sets. Thats based on celestial mechanics, and useful to know
(though only those with a very low southern horizon will see Scorpius during the summer months). Meanwhile, the Navajo people of the Grand
Canyon area of Arizona, USA (Chap. 15) call the Big Dipper and Cassiopeia
constellations Revolving Male and Revolving Female, respectively, which is
as instructive about the circumpolar nature of the northern sky as any
stargazing book could be. Such stories that relate to the exact positioning
and motion of stars in the night sky can be just as useful as science.
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References
Consolmagno, Guy & Davis, Dan M.Turn Left at Orion: 4th Edition. Cambridge
University Press, Cambridge. 2011.
Rees, Martin J (Ed). DK Illustrated Encyclopedia of the Universe Dorling
Kindersley, London. 2011
Seronik, Gary. Binocular Highlights: 99 Celestial Sights for Binocular Users Sky
& Telescope Stargazing. Sky Publishing, USA. 2007.
Sessions, Larry/EarthSky. Rigel in Orion is blue-white. [ONLINE] Available at:
http://earthsky.org [Accessed 01 June 15]. 2015.
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Eta Aquarids
Early-rising stargazers get a treat this month. Peaking in early May
though ongoing from late April until the middle of Maythe Eta Aquarid
meteor shower can spray about 1020 shooting stars every hour into
Earths atmosphere. Appearing to originate from the zodiacal constellation
of Aquarius (Chap. 6), theyre strongest in Moon-less skies in the early
hours of the morning. This debris is leftover from Halleys Comet, which
Springer International Publishing Switzerland 2015
J. Carter, A Stargazing Program for Beginners, Astronomers Pocket
Field Guide, DOI 10.1007/978-3-319-22072-7_5
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side of your field of view. Its currently about the distance of Pluto away,
and will be traveling in the direction of Procyon for decades yet, passing it
line of sight (see below) in 2045 before rushing back into the inner solar
system for its next brief performance.
Meet theGrandparents
A globular cluster is the oldest thing you can see in the night sky. A halo of
tightly packed stars that looks a bit like a galaxy in its own rightand a
truly beautiful sight in a telescopeglobular clusters are star clusters that
formed and remain in the outskirts of the Milky Way (Chaisson and
McMillan 1999), and no longer produce new stars. Astronomers know of
about 150in our own galaxy, which are found far away from the galactic
plane. The stars found in globular clusters, such as in the Great Hercules
Cluster, are much older, and redder, than stars found in the Milky Wayas
much as 1315 billion years old (Talpur 1997). Star formation would have
stopped in these clusters soon after their inception, so only old stars
remain (Chaisson and McMillan 1999).
Some globular clusters are named after their shape or appearance, such as
Omega Centauri, only viewable from the southern hemisphere (Chap. 13).
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Fig. 5.2 Lyra, Hercules, the Keystone and globular cluster M13
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Fig. 5.3 The constellation of Coma Berenices includes the Coma Star
Cluster/Melotte 111, a fine binocular target
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Zone ofAvoidance
Less used, but critical to understanding the limits to stargazing and
astronomy, is the Zone of Avoidance. It describes the fifth of the night sky
that is blocked from further investigation by the presence of the stars and
dust within the Milky Way. That means that the plane of the Milky Way
the galactic planeis the most difficult place to search for objects. Its
much easier to search and find on the other side of the night sky, which
looks away from the Milky Ways center and out into the Universe. Its
interesting to think that if the solar system was closer to the galactic
center, the Milky Way would not only be brighter in the night sky, but it we
would see even less with our telescopes; wed know far less about the
Universe at large.
This doesnt mean that the Zone of Avoidance is to be avoided; its been a
prime target for radio astronomy, which is uncovering much that was hidden from the view of optical telescopes. The Zone of Avoidance still exists,
but its getting smaller thanks to both radio and infra-red astronomy.
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positive number. Stars that are brighter than Vega have a negative
magnitude; for example, Sirius has a magnitude of 1.4, the Full Moon 12,
and our Sun a whopping 26 (so bright it blocks our view of everything
else). Stars less bright than Vegawhich is the vast majorityhave positive magnitude; for example, Rigel is very similar to Vega +0.1, Betelgeuse
is +0.5 and Castor is +1.6.
Star clusters and galaxies also get the same treatment; the Hyades has a
visual magnitude of +0.5, the Pleiades +1.6 and the Beehive Cluster is +3.7.
The latter is only just visible to the naked eye, but easy in binoculars
(Chap. 4), which gives you a clue about how visual limiting magnitude
translates to what the naked eye can and cannot see (see below).
The major planets are relatively bright, so have negative visual limiting
magnitude, though their exact brightness changes as our distance from
them increases and decreases. If a planet is described as being at
oppositiona term often used in stargazing calendarsEarth is directly in
between it and the Sun; this is the best time for viewing the planet because
it is at its brightest as seen from Earth. Its visual limiting magnitude never
gets higher.
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the center of a light polluted city, 30in the suburbs at +3, and 90 on the
outskirts of town at +4. Leave the city limits altogether and the magnitude
of stars might increase to +5 or +6, which will uncover between a few hundred and a thousand stars. Here youve reached the limit of the naked eye.
Pick-up your more sensitive binoculars and you can suddenly see stars
down to a magnitude of as much as +10 (http://www.astrometry.org/
magnitude.php)thats around 600,000 starsbut only in a dark location.
Using binoculars in the suburbs of a city will mean a visual limiting magnitude of about +7, which is about 25,000 starscertainly enough to be
getting on with. Its all a trade-off between the amount of light thats collected, and light pollution.
The bottom line is this; if youre looking for an object with the naked eye
thats listed as having a visual magnitude of +2 or +3 and you cant see it,
youre either under very light-polluted skies or you need more time to
allow your eyes to adapt to the dark.
Either way, understand visual limiting magnitude and youll begin to realize why stargazers like to travel to find darker skies (Chap. 15); visibility of
stars rises from double figures in a city to many hundreds of thousands
under dark country skies.
Moving Groups
We already know that constellations are simply stars that are line of sight
companions as seen from Earth (Chap. 4), but stars rarely travel solo. Weve
already come across star systems where two or more stars orbit each other,
such as Mizar and Alcor in the Big Dipper (Chap. 1). Weve also looked at
many open clusters, such as the Pleiades (Chap. 2), where stars are moving
through space together. They also look close together to us, so referring to
them as a group is hardly an intellectual leap. However, there are other,
much closer stars that are moving through space together in groups
despite seemingto usto be on opposite sides of the night sky and in
completely different constellations.
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Stellar Motion
Although all of the stars appear to move constantly in the night sky, we
know that its the rotation and orbit of the Earth around the Sun thats
causing the four-minutes creep of the stars each day (Chap. 3) and the
changing seasonal constellations, respectively. However, stars are themselves moving, too. Its happening so slowly that its difficult to measure,
and you certainly wont notice any stars move in an entire lifetime (with
one exception, see below). But they are moving. All the stars in the Milky
Way are orbiting the center, including our Sun, which takes about 250 million
years to make one complete orbit.
The way astronomers measure space motion is by using Earths orbit
around the Sun to create a parallax; a stars exact position as viewed from
Earth is measured six months apart when Earth is either side of the Sun.
Thats convenientit means astronomers can go from one side of the solar
system to the other without any effortthough its only a large enough
difference to see motion in the very closest stars.
The nearer the star, the easier it is to measure; the fastest-moving star we
know of is Barnards Star in the constellation of Ophiuchus (Chap. 6), which
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is just six light years from us, making it the second-closest star we know of
after the Alpha Centauri star system (Chap. 13). In an average human lifetime Barnards Star, a faint red dwarf star (Chap. 8), will move about the
equivalent distance of the diameter of the Moon in the night sky. In celestial terms, that is very fast!
Another scenario where stars appear to move slightly is in binary or triple
systems, where two or three stars orbit each other. As they pass each other,
astronomers can detect a change in the stars brightness. Such stars are
known as variable stars, of which Algol is the most famousits even possible to see it blink as the brightness changes (Chap. 11). In May, the easiest
multiple star system to see is Epsilon Lyrae, known as the double double,
in the tiny constellation of Lyraand its an absolute stunner. Lets take
a look.
A Double Star
We have looked at some far double stars before, when tracing the outline
of Ursa Major (Chap. 3), but perhaps the most famous double star of all
Epsilon Lyraeis rising this month in the tiny constellation of Lyra. Having
just found Vega, its brightest member, you may have already noticed it.
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Besides the double star were about to find, theres another reason why
stargazing at Lyra has a special significance. NASAs Kepler Space Telescope
spent four years between 2009 and 2013 planet-hunting in the direction of
Lyra and found over 1000 (Wall 2015) (Chap. 8).
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Satellites
You can easily see more than 10 satellites per hour in the few hours after
sunset, or before sunrise. There are over a thousand up there, the nearest taking about five minutes to cross the sky. Youll also see much
slower satellites that take twice as long to disappear from view. Most are
communications (such as satellite phone coverage), weather or spy
satellites.
Stargazers can only see about half of all man-made satellites; the other half
are TV, communications and more weather satellites (whose photos we see
every night on TV weather reports). They are all in distant geostationary
orbits, so remain above a specific point on the Earths surface. Theyre too
far away to see with the naked eye.
Next time you see a moving satellite, put down your binoculars (and put
your glasses on, if applicable) and see if you can spot it with your naked
eye. The chances are you can, but only if you know its there.
Occasionally youll see a light that crosses from west to east just after
nightfall that looks about as bright as Jupiter or Venus (Chap. 4). Is it a
satellite? Yes, but not just any satellitethis is one of the closest satellites,
and its usually got six human beings aboard. It is, of course, the
International Space Station (ISS), one of stargazings newest and most
dramatic sights (Fig.5.4).
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Fig. 5.4 The International Space Station is one of the brightest objects in
the night sky. NASA
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able to track a man-made object as it orbits the Earth is surely one of the
joys of stargazing in the twenty-first century. Once youve seen it whizz
from one horizon to the other in just a few minutes, youll never fail to
notice it when its overhead.
ISS Apps
ISS pass predictor apps are many. Apps like ISS Spotter, ISS Finder and ISS
Locator turn a chance encounter with the space station into a regular, predictable event by plotting its progress on a world map. It also checks your
own location and produces a list of that months exactly timed sightings
with an optional alarm. That might sound like overkill, but its also a handy
reminder to go outside and start stargazing.
http://spotthestation.nasa.gov/
www.howmanypeopleareinspacerightnow.com
3
www.heavens-above.com
2
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and travel across to the east. As it does, track it first with your eyes, and
then with your binoculars; youll be amazed both at how bright it is, and
how quickly it moves through your binoculars field of view against the
background of stars. Youre looking at something orbiting Earth about five
miles per second; thats about nine times faster than a speeding bullet.
Photographing theISS
This is completely optionalnot all stargazers will want to take photos, or
have the right equipment (a DSLR camera on a tripod)but those six-or-so
humans are simple to photograph. Since it takes about four minutes to
cross the sky, a long exposure photograph using a wide-angle lens can
easily capture the bright trail of the ISS. Just dont expect any detail; its
about 250 miles above you.
Composing theShot
The best photos of the ISS are already good landscape photos, with orbiting
humans adding an unusual dimension. Try to get some foreground interest,
such as the rooftop of your house, grand public buildings or bridges
(though avoid anything illuminated at night), or some trees or mountains.
Bear in mind that a bright Moon can wash-out the sky in a long-exposure
photograph, though that can give the illusion of a day-time pass of the ISS.
If you want to be really ambitious, you have two options. One is to capture
the ISS passing a crescent Moon (see below), which can only occur in the
western sky so youll have to capture the ISS almost the second it comes
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Fig. 5.5 The International Space Station passes 250 miles above Cardiff,
South Wales. Jamie Carter
into view. The second is to attempt a star-trail photograph that captures
the movements of stars (Chap. 8), something that takes over an hour to
capture; if the ISS happens to pass over during that time, you might get
something really special slicing through your star-trail!
Taking theShot
The tripod is crucial since youll be opening the shutter for 30-seconds.
With the camera in manual mode and the lens on manual focus and set to
Infinity, set the ISO at 400 and the aperture at f/2.8 or lower. Take a test
exposure for 30 seconds. When the ISS is due, begin to scan the horizon
with your eyes while crouched behind the camera. When it appears, line-up
the photo as quickly as possible and open the shutter for 30seconds. When
thats done, swivel the camera so its facing the east and wait for the ISS to
drop into the field of view; even if it begins to fade to the naked eye, your
camera will likely still pick it up.
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Fig. 5.6 Look at a one day-old Moon and youll see a super-slim crescent.
Credit: ESO/G.Brammer
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References
Chaisson, Eric and McMillan, Steve. Astronomy Today, 3rd Ed. Prentice-Hall,
New Jersey. 1999.
Dutch, Stephen. Finding Your Way Around The Sky. [ONLINE] Available at: http://
www.uwgb.edu/dutchs/astronnotes [Accessed 01 June 15]. 2009.
Harrington, Philip S.Star Ware, 4th Ed. John Wiley & Sons, NewYork. 2007.
Lunine, Jonathan. Earth: Evolution of a Habitable World Cambridge University
Press, Cambridge. 2013.
Southern Stars Group SkySafari [computer software]. Southern Stars Group,
LLC. 2009-2014.
Talpur, J.A guide to globular clusters. [ONLINE] Available at: http://www.astro.
keele.ac.uk [Accessed 01 June 15]. 1997.
Ventrudo, Brian. See the Eta Aquarid Meteor Shower. [ONLINE] Available at:
http://cosmicpursuits.com [Accessed 01 June 15]. 2015.
Wall, Mike. 1,000 Alien Planets! NASAs Kepler Space Telescope Hits Big Milestone. [ONLINE] Available at: http://www.space.com [Accessed 01 June 15].
2015.
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Fig. 6.2 The Summer Triangle dominates the eastern sky after sunset from
mid-June
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and even closer Altair, Denebs huge distance shows how lopsided the
Summer Triangle really is.
There are gems inside the Summer Triangle that well return to over the
next six months as the asterism drifts to the south and west and sinks on
its side in December, but for now, just get a handle on where it is in the sky.
The asterism is actually at its besthigh in the southin late August and
September, so should perhaps be called the Fall Triangle. Whenever you go
outside this month, look to the east and try to find it; its our anchor for
almost the rest of the year.
Northern Exposure
With the ever-changing sky to the east and south, its easy to ignore the
circumpolar stars and constellations in the north. However, theyre movements are just as seasonal, and theres still plenty more to discover around
Ursa Major.
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two stars. Just find the brightest, Cor Caroli, by tracing a line to the horizon
from Alkaid in the Big Dipper to Denebola at the tip of Leos tail (Fig. 6.3).
Cor Caroliwhich is 110 light years distantis about two-fifths of the way
down that line from Alkaid.
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Fig. 6.3 Canes Venatici, the Baby Giraffe, a double star, and the location of
the Hubble Deep Field
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Fig. 6.4 The stitched-together images that make-up the Hubble Deep Field
of 1995. Credit: Robert Williams and the Hubble Deep Field Team/NASA
The Hubble Deep Field was followed in 2004 by the Hubble Ultra Deep
Field1 and in 2012 by the Hubble eXtreme Deep Field,2 both of which
showed a similar treasure trove of galaxies, this time in the direction of the
southern hemisphere constellation of Fornax (Chap. 13).
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Precession oftheEquinoxes
In stargazing, things change slowly, but they do change. For instance,
Polaris wont always be the North Pole star since the Earthcaused by
the gravitational forces of the Moon and Sunwobbles on its axis, and
so gradually points to a different star in a circular motion that last for
25,800years; pole stars are therefore transient. That long-term wobble
also has an effect on the equinoxes because the Suns apparent path
through the sky shifts slightly. The result is that the exact position of
the background stars at each solstice and equinox changes over the
years.
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The Tropics
The Tropic of Cancer and the Tropic of Capricorn are named after the constellations that the Sun is in during the summer and winter solstices, respectively.
However, precession has seen the constellations appear to shift so much that
the names no longer make any sense. If we were to re-name them accurately,
the northern hemisphere would get the Tropic of Taurus and the southern
hemisphere the Tropic of Sagittarius. Its the first clue that theres something
gone awry in the night sky that most of the world seems oblivious to.
The Zodiac
The location of the ecliptic is always worth contemplating while stargazing,
but its also worth knowing about the zodiac. Its defined as the group of
constellations that lay behind the ecliptic; if you draw a line from Earth
through any part of the ecliptic and far beyond, it will point to one of the
zodiacal constellations. While as a popular concept it may appear to have
more to do with astrology than astronomy, thinking about the zodiac takes
what you instinctively knowyour star-signand gives it a real place in the
night sky.
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Astrology andStargazing
Astrology says that a persons characteristics and future can be foretold
using a map of where the Sun and planets were on the day of their birth.
This is a horoscope.
That practice may be much derided by astronomers, but the ancient practice of astrology does have its basis in celestial mechanics. However, by
observing the zodiacs inaccuracies with the naked eye, stargazers can
learn about the true workings of the night sky.
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Fig. 6.5 While the star sign of Gemini rules in June, the Sun is actually still
in Taurus
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Astrologys Inaccuracies
Although its based on actual constellations in the night sky, astrology
makes a lot of errors. Stargazers know that the constellations, and the
appearance of planets and the Moon within them, are merely line-of-sight
views from Earth; when Jupiter is in Virgo, its actually nowhere near the
stars of Virgo. It just looks like it is. Astrology overlooks this, but its biggest
mistake is the fixed dates of the star signs. In the process of codifying astrological charts the ecliptic was split into 12 equal parts of 30 each, with
each section assigned a constellation. The result is horribly vague. Astrology
is about convenient, easy to use horoscopes, with any sense of the interplay between the Sun and stars lost long ago.
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success will try to interfere, dont worry too much; from a stargazers point
of view, a horoscope could only ever be said to have meaning to someone
that lived over two Millenia ago in southern Iraq.
The bad news for astrology is that Thuban will appear to shift further from
the north pole until about 10,000 AD, not returning to its status as pole
starand the lynchpin of astrologyuntil the year 20,346AD.Dont forget
to check your horoscope then!
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Check withtheMoon
When planning stargazing sessions to dark skies (Chap. 15), avoid the week
between Last Quarter Moon and Full Moon, though the few days either
side will feature a bright Moon in the sky, too. Having a Lunar calendar
handy can help you make a snap decision to the question when shall we
go on vacation? without having to utter the (often unexpected!) words let
me check with the Moon.
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What YouNeed
Night sky photography requires a camera with a mode that allows you to
keep the shutter speed open for long periods; since its dark, youll need to
take long exposure images, though none longer than about 25 seconds.
Any DSLR is perfect for photographing the stars, though a compact camera
with a firework mode can also work well. A tripod is necessary (keeping
your camera completely still is critical so don't attempt to hand-hold it),
though a small, portable model is fine.
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Fig. 6.7 Wide-field images of the night sky can capture the Milky Way.
Gill Carter
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Fig. 6.8 The Moon makes a good subject for photography at sunset or
sunrise when its less bright. Jamie Carter
Composing theShot
A shot of Cassiopeia on its own is a good result, but a photograph of it
between two tall trees is even better. Buildings, lakes, trees, mountains
all serve as excellent foregrounds and frames (Fig. 6.9). How much of the
foreground you can photograph will depend on your lens; the wider the
angle, the more of the landscape youll be able to get. Photographing a
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Fig. 6.9 A building in the foreground can help composition of night sky
images, though any uplighting is magnified during the long exposure.
Gill Carter
landscape and stars on the horizon rarely works because stars in that area
of the sky look dimmer (the exception is a bright planet like Venus or
Jupiter). Try to get close-in to your subject and shoot upwards. Wide-angle
shots are best taken using a 1022mm lens or similar.
Taking theShot
Simply pressing the shutter release button introduces enough judder to
ruin any long exposure image, so be sure to activate the cameras self-timer
function. A two-second delay is fine. DSLR owners may have a remote shutter release cable for the same purpose. While the shutter is open dont be
tempted to switch on your flashlight or play with your smartphoneit will
degrade your image.
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Experiment withSettings
Experiment with shutter speeds of between 10 and 25 seconds. If the
results are too dark, use a longer shutter speed and increase the ISO.
If thephoto has too much light in it, decrease the shutter speed and the
ISO. Doing the latter will reveal the colors of stars and reduce unwanted
noise in your photos.
Reviewing theResults
Your images will need editing, and your blurry images discarding (it
happens!). Cropping may help to produce a better composition. Also try
increasing the exposure and contrast in post-processing software such
as Photoshop, GIMP or Lightroom. Youll probably find that your camera
has captured many more stars than you could see, and perhaps even
the Milky Way if you were somewhere really dark.
References
Kaler, Jim. Stars. [ONLINE] Available at: http://stars.astro.illinois.edu/sow/sowlist.html. [Accessed 01 June 15]. 2015.
The Sky At Night: Hubble: The Five Greatest Images of the Cosmos. Television
program. British Broadcasting Corporation, London, April 2015.
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Royal Stars
June and July sees the appearance of Antares, a red supergiant star with a
special reputation among ancient stargazers. Its a member of the Royal
Stars of Persia (Bobrick 2006), four stars of roughly equal brightness that
lie on four equally-spaced points of the ecliptic. The other three are
Aldebaran in Taurus (Chap. 2), Regulus in Leo (Chap. 3) and Fomalhaut in
the southern hemisphere constellation of Pisces Austrinus, which peeks
above the southern horizon in October below Aquarius (Chap. 10). Their
significance comes from their positions near the Sun on the dates of the
solstices and equinox. For example, the Sun was in Leo during the summer
solstice (Chap. 6) so Regulus was dominant. With precession (Chap. 6) this
no longer applies, though the equal spacing of the Royal Stars remains
visible; at the summer solstice Regulus appears just above the south-west
horizon, while at the winter solstice Fomalhaut is visible in the same area
(though its very low on the horizon). At the vernal equinox (Chap. 3) youll
find Aldebaran in the south-west, and during the fall equinox (Chap. 9)
Springer International Publishing Switzerland 2015
J. Carter, A Stargazing Program for Beginners, Astronomers Pocket
Field Guide, DOI 10.1007/978-3-319-22072-7_7
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Around 550 light years distant, Antares is one of the biggest stars we
know of. A red supergiant, its often confused with Mars because of its
metallic orangey-red appearance (especially through binoculars) though
its slow-moving Saturn (Chap. 9) that is nearby from 2015 until about
2021. Antares is best seen from JuneSeptember, and is yet another double star system; its worth returning to Antares with an eight-inch telescope later in the year if you want to glimpse its much smaller,
green-looking companion.
So big is the primary star of Antares that it would stretch to the orbit of
Mars if it was put at the center of our solar system (Sessions 2014). As well
as being big, Antares has even more in common with Betelgeuse (Chap. 2)
in that both are very young; Antares is just 12 million years old to
Betelgeuses 10 million years. Antares belongs to the Scorpius-Centaurus
Association, a loose grouping of relatively close stars in Scorpius and Crux,
the latter constellation of which is only visible from the southern hemisphere (Chap. 13).
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Brief Encounters
From a stargazing point of view, the Royal Stars position on the ecliptic
means only one thing; theyre ripe for being both passed closely by the
planets and blocked from view by the Moon. The former is called a conjunction (Fig. 7.2) and the latter an occultation, and theyre well worth
looking out for on an astronomical calendar.
Fig. 7.2 The Moon in conjunction with Venus and Jupiter. Credit:
ESO/Y.Beletsky
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Fig. 7.3 Thin crescent Moon setting over ESOs Paranal Observatory in
Chile while in conjunction with Mercury and Venus. Credit: ESO/B.Tafreshi
(twanight.org)
However, occultations of planets by the Moon are relatively rare and can
only be seen from specific places on Earth for short periods of time, usually
just a few minutes.
Catching aConjunction
Less precise, but just as beautiful to look at is when two or more celestial
bodies appear close together in the night sky for one or two evenings. This
apparent celestial near-miss is called a conjunction (Figs.7.2 and 7.3), and
like an occultation its nothing more than a line-of-sight alignment, only
looser. Rarer are conjunctions of two planets,1 though over the course of
time complex super-conjunctions are inevitable.
The exception being the inner planets, Mercury and Venus, which often appear to
be very close to each other just before sunrise and just after sunset.
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Super-Conjunctions
A great benefit of having planetarium software is the chance to fast-forward
the sky. Not only can you see whats going to be in view tomorrow, next
week or during your next planned vacation, but you can go hunting for
rare celestial gems. One such gem occurs on September 8, 2040 when the
western horizon after sunset will be studded with no fewer than five planets
visible in the same area of sky along the bottom of the constellation of Virgo.
This is whats called a super-conjunction. They wont be perfectly aligned, but
its near enough; Mercury will be nearest the horizon followed by Jupiter
just above it and, just to the south-west, a one-day old crescent Moon will
appear to shield Saturn, Venus and Mars. It promises to be quite a sight,
and a date for the long-range stargazing diary alongside solar and lunar
eclipses. However beautiful and fleeting a conjunction can be, its crucial to
remember one thing; they have absolutely no celestial significance.
Rivals inRed
The brightest star in the constellation of Scorpius, Antares is on the ecliptic.
All of the outer planets appear to pass close to Antares at some point, so
why the confusion with Mars? As well as Antares and Mars both being
orangey-red to look at, its 687-day orbitby far the shortest of all the
outer planetsmeans that Mars passes close to Antares less than once
every two years. Jupiter is close to Antares once every 12 years, while
Saturn every 29 years.
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Fig. 7.4 The Milky Way is several spiral arms of giant stars, with the Sun in
the Orion Spur (just above the Perseus Arm on this diagram). Credit: NASA/
Adler/U.Chicago/Wesleyan/JPL-Caltech
its 250 million miles distant, so if any humans do ever travel to Mars, they
wont return for at least 18 months, when its nearer.
Its vastly differing distances from Earth means that the brightness of Mars
appears to noticeably wax and wane in the night sky. However, since its
further from the Sun than the Earth, we never see it as a crescent, as we do
Venus and Mercury (see below). Through a pair of binoculars Mars looks
red, and not particularly impressive; return with a small telescope (Chap.11)
and its possible to see surface markings and ice-caps when it is near.
Galactic Geography
The Milky Way is a confusing place. Its a barred spiral galaxy, which means
that theres an oblong-shape bar or bulge of stars, with several armsall starforming regionsin the galactic disk that spiral around the center (Fig.7.4).
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Weve already looked in winter at the Orion Spur (Chap. 2), and next
month well visit the Sagittarius Arm while looking at the Summer Triangle
(Chap. 8). Well also come across the Perseus Arm before too long
(Chap. 11). However, its best to not become too obsessed about exactly
which spiral arm is where in the night sky when looking in the direction of
our next targets, Sagittarius and Scorpius. Here lies the Galactic Center,
but the view towards it is through parts of several inner spiral arms that
become impossible to pick apart in the middle. However, some basic
geography is still useful to put what youre seeing into context.
Southern Star-Fields
As springs scant-looking constellations are displaced by the stars of summer, some particularly rich and dense star-fields swing into view. Cygnus
well look at below, but for now try to get a fix on two key constellations of
the zodiac (Chap. 6), Sagittarius and Scorpius. Stargaze towards Sagittarius
and youre looking at the densest, richest part of our galaxy (Fig.7.5) where
Fig. 7.5 Scorpius and Sagittarius lay across the center of the Milky Way
where the night sky is busiest. Credit: ESO/Serge Brunier
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star clusters and star-forming nebula are abundant. Find a comfy place to
sit because a few hours spent staring at this region with a pair of binoculars
doesnt even begin to do it justice. These few targets serve only as brief
highlights in this, the busiest yet most fleeting region of the night sky for
stargazers in mid-northern latitudes.
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Fig. 7.6 Around the Teapot asterism in Sagittarius are many stars, open
clusters and nebula
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Swapping Hemispheres
For the clearest views of Scorpius, Sagittarius and the Milky Way as well as
nearby galaxies, brighter globular clusters and nebulas, youll have to head
south of the equator and get to grips with the southern hemisphere night
sky. This upside-down journey south can be disorienting as familiar constellations confuse amid a plethora of new and baffling stars, while the
Moon appears upside down. Every stargazer should head south to observe
at least once if they can (Chap. 13).
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the Sun, these two planets appear to ping back and forth fast, popping in
and out of the Suns glare, often being visible at sunset for weeks (Mercury)
or months (Venus) on end, before disappearing for long periods. Mercury
is smaller even than Jupiters moon Ganymede (Chap. 4), and its orbit is so
close to the Sun that we rarely see it; unless theyre behind the Sun,
Mercury and Venus are always in our sky, but are so near to the Sun that
theyre made invisible by daylight.
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Planets GoBackwards
Though they appear to drift from east to west across the night sky, the
planets orbit the Sun in the opposite direction along the ecliptic. From
Earth we dont get to witness complete orbits of planets precisely
because were on a journey around the Sun ourselves. Consequently, the
circuit of a planet passing through our night sky has an odd feature; all of
the planets occasionally appear to go backwards. It can happen to a
planet for weeks on end, something called retrograde motion by
astronomers.
Why is this? Precisely because the planets are going around the Sun and
thatcruciallywe are too, our line of sight to them changes. Since all
planets orbit at different rates, Earth is constantly catching them up and
overtaking them as it hurtles around its relatively small orbital path.
Consequently, their orbital speeds appear to speed-up and slowdown, and
they appear to go backwards, before returning to their normal trajectory.
A car traveling at 80 mph will appear to go backwards when viewed
through the window of a passing car going at 90mph. You get the idea.
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Fig. 7.7 From Earth, Venus appears to have phases; when it appears
furthest from the Sun, its half-lit, reducing to a crescent as it gets closer.
Credit: ESA/MPS/DLR/IDA, M.Prez-Aycar & C.Wilson
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Delta Aquarids
Late July sees the peak of the Delta Aquarids. Meteor showers come and
goand many disappoint or are blocked by bad weatherbut any chance
of shooting stars in summer shouldnt be overlooked. This is the season to be
outside stargazing late at night, and thats most easily done if youre camping. If thats your idea of fun, plan to camp during the Delta Aquarids, which
peak at the end of this month and can produce 1520 meteors per hour.
Fig. 7.8 Venus & Mercury in conjunction just after sunset. Jamie Carter
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Splitting Stars
To split stars is to make-out two or more separate stars where there appears
to bewith the naked eyejust one star. Weve previously split Mizar and
Alcor in the Big Dipper and Epsilon Lyrae in Lyra by looking first with the
naked eye then again with binoculars (Chaps. 1 and 4). Its something we
can do right across the sky; there are multiple stars that arent alone. Some
are just two unrelated line of sight stars that appear to be next to each
other, while others are true binary star systems. While the former are an
optical illusion, the latter are gravitationally bound; they orbit each other.
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Fig. 7.9 The Northern Cross within Cygnus, a double star near Deneb and
the tiny constellation of Delphinus
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Fig. 7.10 The Moons major lava seas. Credit: NASA/Bill Ingalls
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References
Bobrick, Benson. The Fated Sky: Astrology in History. Simon and Schuster,
New York. 2006.
De Laet, Rony. The Casual Sky Observers Guide: Stargazing with Binoculars
and Small Telescopes. Springer, NewYork, Dordrecht, Heidelberg & London.
2012.
Espenak, Fred/NASA/GSFC. Six Millennium catalog of Venus transits: 2000
BCE to 4000 CE. [ONLINE] Available at: http://eclipse.gsfc.nasa.gov/transit/
catalog/VenusCatalog.html [Accessed 01 June 15]. 2012.
McCann, David. Mercurys orbit and phases. [ONLINE] Available at: http://www.
skyscript.co.uk [Accessed 01 June 15]. 1999.
NASA News Release Number STScI-2003-19: Oldest Known Planet Identified.
[ONLINE] Available at: http://hubblesite.org [Accessed 02 June 15]. 2003.
NASA News Release Number: STScI-2013-08: Hubble Finds Birth Certificate of
Oldest Known Star. [ONLINE] Available at: http://hubblesite.org. [Accessed
05 June 15]. 2013.
The Planetary Habitability Laboratory (PHL), University of Puerto Rico at
Arecibo. The Constellations of Exoplanets. [ONLINE] Available at: http://phl.
upr.edu [Accessed 02 June 15]. 2014.
Sessions, Larry. Antares is Heart of the Scorpion. [ONLINE] Available at: http://
earthsky.org [Accessed 02 June 15]. 2014.
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Predicting theMoonrise
Like everything else in the night sky, a rising Full Moon is predictable down
to the second. Simply find out on what date the next Full Moon is going to
be (its probably already printed in your diary) and exactly what time
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Fig. 8.2 A Full Moonrise is one of stargazings most awesome sights. Credit:
NASA/Bill Ingalls
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sunset is on that date, then look to the east in the opposite direction to
where the Sun is setting.
The colorful spectacle lasts mere minute and is easy to miss. If youve ever
seen photos of someone silhouetted against a seemingly giant Moon, perhaps while standing on top of a hill, they were taken in these brief
moments, so were likely no accident. To make the Moon look so large in the
background photographers use super-zoom lenses of around 400 mm
while positioned a mile or more away. For the rest of us, a pair of binoculars
reveals a memorable sight each month (Fig.8.2).
If you miss the Full Moon rising (probably because of a cloudy horizon)
either wait for the equally beautiful Moonset at dawn, or look again the
next night about 50minutes after last nights Moonrise. Missed it again?
Wait a further 50minutes, though by then the Moon will be on the wane
and rising in darkness, so the chance to see Moon-glow and color on
nearby clouds is lessened.
The Full Moonrise is also a watershed for stargazing. Since its about to
disappear from the early evening skies completely for a few weeks, this is
the best time to head for your nearest truly dark sky (Chap. 15) for uninterrupted stargazing.
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Fig. 8.3 A Super Moon can only be seen when the Moon is both at its
closest to Earth and in the Full Moon phase. Credit: NASA/Bill Ingalls
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to watch the large New Moon pass in front of the Sun in the morning
followed by an overly large Super Full Moon at sunset. Think about the
Moons orbit and youll quickly realize that would be impossible.
A Fireball Festival
If theres one date range that should be in every stargazers diary, its
August 913, the dates of the Perseids meteor shower (Fig. 8.4). Its the
most prolific of the year. Deemed the Tears of St. Lawrence by Catholicism
because of its timing near a saints day, the Perseids are the result of Earths
orbit of the Sun hurtling through a stack of debris left over from a comet
called Comet Swift-Tuttle, which passed through the solar system most
recently in 1992 on its 133-year orbit of the Sun.
The Perseids offer about 50100 or more meteors per hour. Treat a meteor
shower like wildlife-spotting; the more you look, the more you see.
Fig. 8.4 The Perseids meteor shower is caused by Earth speeding through
a stream of debris left by Comet Swift-Tuttle. Credit: ESO/S.Guisard
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Thespectacle of seeing three bright meteors streak across the sky inside a
few seconds is price-less but demands patience, so avoid the temptation to
check your mobile phone or do anything else that takes your gaze from the
skies.
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Zodiacal Light
Light pollution can be beautiful. Although its possible to visualize exactly
where the plane of the solar system is just by looking at the planets and
tracing the line of the ecliptic across the sky, it is also possible to see the
solar system glow. Called zodiacal light, faint columns of brightness
(Fig.8.5) can be seen in the west after dusk in spring and in the east before
dawn during fall, though you will need low horizons.
These are caused by the Suns light hitting dust particles in the solar system
and scattering across the plane. Zodiacal light is sometimes mistaken for
light pollution, though youll only see it if youre far from towns and under
Moon-less skies.
Fig. 8.5 Zodiacal light can sometimes be seen just after twilight. Credit:
ESO/Y.Beletsky
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Triangle Targets
By now the celestial trio of Altair, Deneb and Vega will have become very
familiar, but theres yet more to find within the Summer Triangle including
an elusive space between the stars.
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Hanging onaStar
Nestled within the Summer Triangle, the beautiful Coat-hanger asterism is
summers answer to the Pleiades. One of the few objects in the night sky
whose name is accurately descriptive rather than just fanciful and imaginative, nine blue stars and one orange star trace-out the surprisingly well
defined shape of a Coat-hanger, though its upside-down to us in the
northern hemisphere.
Fig. 8.6 Within the Summer Triangle is globular cluster M71, the tiny constellation of Sagitta, and the Coat-hanger Cluster
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Types ofStars
Stars are not the same. If stars were the same size and brightness, and had
identical lifespans, stargazing would be easy. If bright stars were closer and
dim stars were further away, we would be able to see the solar system in
three dimensions and in real-time without much trouble. The galaxy isnt
nearly that simple.
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Categorizing Stars
Stars are also categorized according to their temperature and their mass.
From hottest to coolest it goes blue, white, yellow, orange, then red (Chap.2).
Stars are given a letteror a combination of lettersto describe their
temperature and mass, with the seven groups being O, B, A, F, G, K and M,
starting at the hottest and ending at the coolest. Thats a lot of letters, but
know that few stars exist at the extremes.
The Extremes
Massive stars dont live long. O-type and B-type stars are hot, blue giants
and supergiants, and though they make up a minuscule percentage of
stars, you already know a lot of them. All the stars in Orions Belt and in the
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wider Collinder 70 cluster (Chap. 12), Meissa above, and even the four visible in the Orion Nebula itself, are all either O-type or B-type stars. All are
fated to have short lives, and destruct in supernova explosions. So are the
equally rare red supergiant starsknown as M-typeswhich include
Betelgeuse, Antares, the Garnet Star and VV Cephei A (Chap. 11).
G Stars: TheSun
So-called yellow dwarf starsA, F and G-typesmake-up the majority of
stars in the Milky Way. Its often said that the Sun is a mid-sized, middle
aged star, but when compared to most of the stars you can see in the night
sky, the Sun is incredibly old. Its classed as a yellow G2 dwarf star, and not
even halfway through its 10 billion years-long life.
Though its nothing special when compared to the whoppers we can easily
see in the night sky, the Sun is special both because of that, and because
the vast majority of stars are red dwarfs, which are both cooler and smaller
(too small to see in the night sky). Since 85 billion of the 100 billion stars in
the Milky Way are red dwarfs, stargazers cant see the galaxy for what it
really is.
Like all stars that arent O-type and B-type stars, the Sunwhich is bigger
than a red dwarfwill eventually run out of fuel, cool and expand to
become a red giant, and then shrink to become a faint white dwarf. Though
most of the stars we stargaze at are blue or red giants, there are three
G-type stars in the northern hemispheres night skyspecifically in the
constellations of Cassiopeia and Pegasusthat are remarkably similar to
our Sun, which well meet later in the year (Chap. 12).
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Comets
Rare but often spectacular, comets that reach the inner solar system from
either the Kuiper Belt or the Oort Cloud are special targets for stargazers.
On a brief trip into the inner solar system to orbit the Sun, a comet often
looks like a bright tadpole-like object, usually with one or two tales; theyre
terrific targets for telescopes and binoculars and, if youre very lucky, just
the naked eye. Its notoriously difficult to predict how bright these balls of
gas, dust and ice will get even when they do appear, hence Charles
Messiers famous non-comet catalogue, which was designed to help his
own search for comets (Chap. 4).
Exceptionally bright comets in recent years have included Halleys Comet
in 1986 (Fig. 8.7 and Chap. 5), which will return in 2061, and Hale-Bopp in
1997, whose orbit is 2537years. The former comes from, and returns to, the
Kuiper Belt, so is classified as a short-period comet. The latter, from the
Oort Cloud, is a long-period comet.
So little is known about comets, the Kuiper Belt and the Oort Cloud that an
exceptionally bright comet could appear at any moment. In fact, well only
know its here when a stargazer like you or me reports seeing it.
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Fig. 8.7 Halleys Comet will return from the Kuiper Belt in 2061. Credit: ESO
Unknown Worlds
Hunting for exoplanets is astronomys current obsession, with research
grants pouring into the search and examination of previously unknown
worlds. From giant planets (often called hot Jupiters) that orbit their sun in
just a few hours to planets in quadruple star systems, whats being discovered is profoundly changing how we look at the Universe, and at our own
solar system. Exoplanets are beyond our reach when stargazing, of course,
but its revealing to know where in the night sky astronomers are looking.
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over 4175 candidate planets were identified within its tight field of view,
and over 1800 had been confirmed as exoplanets by 2015. How theyre
discovered is clever, and has awesome consequences; a star dips in brightness slightly as a planet transits across it, which is enough to allow calculations about the mass of those planets, and the speed of their orbits. Using
that technique astronomers can detect planets that orbit in the same
planei.e. planets that the Kepler Space Telescope has a side-on view
ofbut no others. Planets that dont transit, from Keplers limited point of
view, cant be detected. There can only be one conclusion. There arent
hundreds, thousands, or even millions of planets in the Milky Way. There
are at least 40 billion planets, according to researchers from UC Berkeley
and the University of Hawaii extrapolating Keplers data (Petigura 2013).
Theyre likely in every direction a stargazer looks (Fig.8.8).
Fig. 8.8 Planets around the stars in the Milky Way appear to be the rule
rather than the exception (artists impression). Credit: ESO/M.Kornmesser
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Fig. 8.9 Earth-sized planets have likely formed throughout most of the
Universes 13.8 billion year history (artists impression). Credit: NASA Ames/
SETI Institute/JPL-Caltech
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tory, which could mean that life is ancient; by the time that the Earth
formed, the planets orbiting Kepler-444 were already older than our planet
is today.
Fig. 8.10 Star-trail over the La Silla Observatory in northern Chile. Credit:
Iztok Bonina/ESO
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Fig. 8.11 Its possible to produce a rudimentary star-trail even in a lightpolluted urban area. Jamie Carter
Either way, youll need a DSLR camera on a tripod ideally with a wide-angle
lens set to infinity focus, maximum aperture (F3.5 or thereabouts) and ISO
400. To avoid any camera shake, which can easily ruin a star-trail, use a
remote shutter or a timer to delay the shutter release by a few seconds.
Infinity Focus
The infinity focus can be a real problem. If you simply line-up the infinity
symbol with the focus mark on the lens, you may get blurry stars-trails.
That can be a nice effect (Fig.8.12), but for sharp focus you will need to sort
out your focusing beforehand in daylight. Several hours before you plan to
shoot a star-trail, pre-focus on a distant object, such as a tree, a mountain
or the top of a building using autofocus or manual focus. Once youre
happy (take some test shots and check for sharpness), switch to manual
focus and either remember where that focus point is, or tape-down the
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lens with some masking tape. It may sounds rudimentary, but it works. The
same applies for all kinds of astrophotography, including photographing
stars (Chap. 6), eclipses and the Northern Lights (Chap. 14).
Fig. 8.12 Take a star-trail facing south and the stars dont circle, they
stretch. This image from Gran Canaria includes the three rather obvious
(though defocused) blue stars of Orions Belt near the top. Jamie Carter
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References
T.L. Campante and T.Barclay and J.J. Swift and D.Huber and V.Zh. Adibekyan and
W.Cochran and C.J. Burke and H.Isaacson and E.V. Quintana and G.R. Davies
and V.Silva Aguirre and D.Ragozzine and R.Riddle and C.Baranec and S.Basu
and W.J. Chaplin and J.Christensen-Dalsgaard and T.S. Metcalfe and T.R. Bedding and R.Handberg and D.Stello and J.M. Brewer and S.Hekker and C.Karoff
and R.Kolbl and N.M. Law and M.Lundkvist and A.Miglio and J.F. Rowe and
N.C. Santos and C.Van Laerhoven and T.Arentoft and Y.P. Elsworth and D.A.
Fischer and S.D. Kawaler and H.Kjeldsen and M.N. Lund and G.W. Marcy and
S.G. Sousa and A.Sozzetti and T.R. White An ancient extrasolar system with five
sub-Earth-size planets. The Astrophysical Journal Volume 799 Issue 2. 2015.
NASA.Kepler Discovers 1000th Exoplanet. [ONLINE] Available at: http://science.
nasa.gov [Accessed 02 June 15]. 2015.
Petigura, Erik., Howard, Andrew. & Marcy, Geoffrey. Prevalence of Earth-size planets
orbiting Sun-like stars Proceedings of the National Academy of Sciences. 2013.
Sagan, Carl. Cosmos: unabridged edition. Random House Publishing Group,
USA. 2011.
PART III
DEEP SKY
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Fig. 9.2 The Great Square of Pegasus rises as a diamond this month, with
the constellation of Andromeda beside it
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Decision Time
If you decide against getting a telescope, simply ignore the telescope targets
that are peppered throughout the remaining four chapters of this book. It
wont impinge on the rest of your learning since there are as many new naked
eye constellations and binocular sights included as in previous chapters.
Taking it Slow
Whatever you decide to do, your eyes and binoculars should, in your first
year of stargazing, remain your primary windows on the night sky. Those
who decide to buy a telescope in their first year of stargazing should keep
it small, learn how to use it properlyand often sparinglyand take
things slowly. The cosmos isnt going anywhere.
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Choosing aTelescope
What telescope should I buy? This is the most common question asked to
any stargazer or amateur astronomer, and also the most difficult to answer.
There are just so many different types of telescopes these days that it can
be very difficult to choose between them. However, stargazers have it
good; telescopes are relatively cheap nowadays. It is possible to spend as
little as a few hundred dollars, but that doesnt mean you should take the
process of choosing and buying a telescope any less seriously.
There are dozens of different types of telescope, but since this is a book on
stargazing rather than advanced astronomy, lets stick to affordable entrylevel models. If you want to dive straight into the high-end and spend
many thousands of dollars, there is plenty of advice in other books and
online. The best advice is to wait at least a year; better to try out a small
telescope to see if you get the bug.
Star Parties
Try out some telescopes first. The easiest way to do that is to attend stargazing sessions at your local public observatory, if there is one, or by
going along to observing sessionsoften called star partiesheld by
your local astronomical society. The folks there will gladly let you have a
go on various types of telescopes, and tell you everything you could ever
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want to know about the different kinds. A quick peek at the planets
through someone elses telescope may even be enough for you to get
your fix.
Just as you do with your own stargazing sessions, go to a star party with an
idea of what you want to learn. A vague request to show me something
amazing every time you get near a big telescope wont get you very far;
youll be shown that seasons best sights, such as the Orion Nebula, Saturns
rings or a globular cluster such as M42. Similarly, ask an experienced stargazer to show you some constellations and youll likely be shown Orion,
Cassiopeia, the Big Dipper and so on. Its better to arrive wanting to be
shown double stars, constellations unknown to you, ormost likely if
youre attending anywhere with big telescopesglobular clusters, nebula
and other sights only visible with magnification. The rest of this book contains suggestions for those using 10-inch and bigger telescopes for precisely that reason; if such sights are beyond your equipment, save them for
your next star party or public observatory trip.
Free Telescopes
For the most bang for your buck, buy a used telescope, or better still, borrow
one. If you do know someone who has a dusty old telescope in a back room,
ask if you can take it on loan, but promise to return it (it might be terrible!).
Either way, there are two types of starter telescopes, the refractor and the
reflector.
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Fig. 9.3 A refractor is a versatile and compact backyard telescope, but the
image is inverted, which can be disorientating. Gill Carter
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telescopes, but generally gather more light, hence their reputation as light
buckets. If youre after more magnification that a refractor can manage,
and are happy to manually control your telescope (tricky, but a surefire way
of getting to learn the night sky properly), a 6-inch to 10-inch Dob makes a
fine purchase, but note that it comes with the distinct disadvantage of
being rather immobile. A 6-inch model can weigh around 20 kg, and a
10-inch around 30kg.
Its possible to lighten the load of that large optical tubeand hence make
it fit into the trunk of a carby choosing a model with a truss-tube. The
tube is collapsible into two parts, which makes a Dob much easier to both
move to dark sky sites, and store in your home. A truss-tube design adds
about a third to the cost.
Limiting Magnitude
As we learned previously, the magnitude of an object (Chap. 5) is allimportantand that applies to telescopes as much as your own eyes. With
so many objects to look for in the night sky, and with star-charts and star
atlases catering to all kinds of stargazers and amateur astronomers using
various types of equipment, it can be difficult to know what is within reach
of your telescope.
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Refractor telescopes
70mm 2.7-inch
80mm 3-inch
(designed for travel)
90mm 3.5-inch
102mm 4-inch
120mm 5-inch
150mm 6-inch
Reflector/Dob telescopes
Planets &
the Moon
Wide-field
clusters &
glimpsing
galaxies
100mm 4-inch
130mm 5-inch
150mm 6-inch
Deep sky
190mm 7.5-inch
200mm 8-inch
250mm 10-inch
300mm 12-inch
Observatorygrade
magnification
350mm 14-inch
400mm 16-inch
Fig. 9.4 What the various sizes of telescopes are best used for, with metricimperial conversions to make it easier to compare the different sizes
Limiting magnitude is the point where something becomes invisible,
though exactly where that point is will wholly depend on what gear
youre using. While objects of +4.5 magnitude are visible to the naked eye
under most conditions, a pair of 10 50 binoculars extends that to
around +9. Use a 4-inch telescope and that jumps to around +12, an
8-inch manages +14, and through a 10-inch telescope its around +15.
Thats true deep sky. Mostly, this book presumes you dont have a 10-inch
telescope.
Get to grips with limiting magnitude, and how it applies to you in your
backyard, and youll better be able concentrate your efforts on get-able
observing targets rather than searching for something you have no chance
of seeing.
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The equatorial mount is much more serious. It allows you to very easily
track movement in the night sky. First you set your latitude on a dial (this
fixes the height of the telescope barrel), then align one axis to the north
celestial polePolaris, the axis of the Earths rotation. Equatorial mounts
also have motors, but theres no need for a computer; the motor will simply
drive the telescope so as to cancel-out the speed of the Earths rotation,
and thus keep the target stationary in the eyepiece. However, theres a
rather steep learning curve (as well as a price-hike) to equatorial mounts
that make them most favored by experienced amateur astronomers and
astro-photographers rather than curious stargazers.
Eyepieces andMagnification
In terms of what you can actually see in your telescope, the important
figureand one used for the remainder of this bookis magnification. If
you have a 4-inch/102 mm telescope with an 800 mm focal length, and
youre using a 25mm eyepiece, its capable of 32 magnification. If youre
using a 9mm eyepiece its capable of 89 magnification (Fig.9.5). 25mm is
therefore referred to as low power, and 9mm as high power. The maths is
easy; magnification = telescope focal length (mm) divided by eyepiece
focal length (mm). So if youve got a monster 10-inch/250 mm telescope
with a focal length of 1200 mm and both 25 mm and 10 mm eyepieces,
youll be capable of both 48 and 120 magnification, respectively.
Eyepieces of the same diameter can often be used on different telescopes
to get completely different results. However, its the eyepieces that telescope manufacturers tend to skimp on, and next year youll probably want
to upgrade the eyepieces that came in the box.
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Fig. 9.6 A red dot-finder or finder-scope lets you manually aim a telescope.
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Many make the mistake of thinking that the best time to observe it is at Full
Moon. Try it for yourself; point your telescope at the Full Moon and not
only will the surface look rather bland, but the brightness and glare will be
unbearable.
The Terminator
Its best to look at the Moon when part of it is in shadow. The line between
the lit part and the dark part is called the terminator, and that is where
youll find long shadows coming off the Moons craters and mountains;
this is how you can see our satellites surface in 3D. Each day of the
Moons orbit, the terminator will shift as it waxes to Full, then wanes to
New, gradually revealingand re-revealingfeatures on its surface.
Moon-watching through a telescope can easily become a hobby in its
own right.
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Fig. 9.7 Earth-shine and the shadows thrown by the terminator on the
Moons surface are fabulous first targets for a telescope. Credit: ESO/
NASA/M.Kornmesser
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Full Moon (Chap. 8), a short observing session is not only possible, but
hugely rewarding. As its rises the brightness of the Moons disc is dimmed
for an hour or so, and its a beautiful, muted orange. Since its low on the
horizon its at a comfortable height to observe, though some elevation will
help you spot it the second it rises. If youre observing either side of Full
Moon, look out for the long shadows on its upper edges that denote that
its not quite, or no longer, in the Full phase.
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Fig. 9.8 Saturns rings are high on most stargazers observing lists when
near a telescope. Credit: NASA and The Hubble Heritage Team (STScI/AURA)
Acknowledgment: R.G. French (Wellesley College), J. Cuzzi (NASA/Ames),
L.Dones (SwRI), and J.Lissauer (NASA/Ames)
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Note that averted gaze is not always necessary; if youre looking for
colorsuch as in the case of Albireo (see below)dont use averted gaze,
because your peripheral vision is less sensitive to color.
Fishing forStars
If you cant find what youre looking for in the night sky, there are two tactics. One way is to increase the field of view; a bright object will be much
easier to find in a 25mm eyepiece than a 15mm or 9mm eyepiece. Once
youve centered the telescope on your target, you can then experiment
with higher power eyepieces. However, if your target is a faint fuzzy, widening the field of view probably isnt going to work; while the target may be
technically visible, it may not be bright enough for you to spot. So go with
the higher power eyepiece and hunt aroundif its faint, theres a greater
chance of you finding it.
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Fig. 9.9 How to find colorful double star Albireo and the Dumbbell Nebula
(M27), both within the Summer triangle
Using Handrails
Get into the habit of studying a star-chart or phone app (on night mode
and with the brightness turned down, naturally), then using binoculars to
locate the region of sky where your target is before finally trying to aim
your finder-scope. If you have trouble finding an object that you can easily
find in your binoculars, use a handrail; line-up the object with the roof of
your house, the top of a tree, or a telegraph line. This can make it much
easier to find, and keep finding, something faint. Just bear in mind that
your telescope is going to be lower than you, so will have a different perspective. This approach only works if your telescope is relatively lightweight and can be moved easily around the backyard.
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Reference
Consolmagno, Guy & Davis, Dan M.Turn Left at Orion: 4th Edition. Cambridge
University Press, Cambridge. 2011.
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http://www.heavens-above.com
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Good Seeing
When stargazers talk about the night having good seeing, theyre not talking about whether the sky was cloudy or clear. Clouds might be the most
common reason for abandoning an observing session, but there are other
meteorological hazards in the skies above that can make the stars more
difficult to observe.
Seeing refers to how turbulent the atmosphere is. If you look at a bright star
low on the horizon, such as Sirius in winter or Spica in spring, you will notice
them twinkle. This is because youre looking through a dense part of the
Earths atmosphere; youre looking at the star through more moving, and
much warmer, air than when you look directly upwards at the zenith. That
moving air interrupts the path of light from the star to your eyes. However,
if its windy there is likely to be a lot of moving air all around you, so the stars
above will twinkle, and be slightly blurry. This turbulent air constitutes poor
seeing, and its the reason why big telescopes tend to be on the tops of
mountains, well above the most turbulent part of the Earths atmosphere.
As a vague rule of thumb, if its been raining, or is predicted to rain near
your observing location later that night, the chances are that the winds will
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be stronger than normal, so seeing could be a problem. However, rainstorms and cold fronts often clear the atmosphere of dust, which can lead
to a very clean, pristine atmosphere ideal for stargazing.
A lot will depend on where you observe from, and pure luck, so dont let
worries over seeing interrupt your plans too much. Just bear in mind that
even in clear skies stargazing can sometimes become a blur. You can maximize your chances of clarity by observing stars and planets when theyre
highest in the sky; Jupiter or Saturn at the zenith is far clearer than when
just above the horizon. The wait for good seeing is why having telescope
often means going to bed very late, or getting up in the small hours.
In Search ofAndromeda
Stare at the Andromeda galaxy and not only are you looking at the light
from 2.5 million light years ago. Youre also seeing the largest galaxy in our
neighborhood that compares to our own; what astronomers know about
the geography and evolution of the Milky Way has much to do with what
theyve been able to learn from looking at this close spiral galaxy.
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Fig. 10.2 How to find the Andromeda galaxy (M31), Triangulum galaxy
(M33) and NGC 752
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Fig. 10.3 In a few billion years M31 in Andromeda will be so close to the
Milky Way that it will cast galaxy-shadows on Earth. Credit: NASA; ESA;
Z.Levay and R. van der Marel, STScI; T.Hallas, and A.Mellinger
The Triangulum
High in the eastern sky this month, and directly below the constellation of
Andromeda and M31, is the tiny constellation of Triangulum, whose name
gives a clue to its basic shape. Nearby is the Triangulum galaxy, M33, the
third-largest galaxy in the Local Group after the Andromeda galaxy and
our own Milky Way.
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binoculars) and youll find that its actually a loose optical triple star.
Although its far smaller than the surrounding constellations, its worth
getting a fix on Triangulum to guide you straight to two stunning deep sky
sights.
Horse toWater
You can by now easily find the Great Square of Pegasus, so its worth looking
underneath it for two asterisms within what are known as the wet constellations, Aquarius the water bearer and Pisces the two fishes. Both of these
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constellations are faint, but as high in the south this month as they ever get.
Aquarius and Pisces dominate this area of the sky, known to stargazers as
The Sea, which also includes the beautiful constellation of Delphinus the
Dolphin (Chap. 7) as well as two that get lost in the horizons haze for almost
all stargazers in the north, Cetus the whale and Eridanus the river.
Fig. 10.4 In an area of the sky called The Sea by stargazers is the Circlet in
Pisces and the Water Jar in Aquarius, above Royal Star Fomalhaut. Also
shown are the rough positions of Uranus and Neptune from 2016 onwards
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Fig. 10.5 The Virgo Cluster and the Fornax Cluster dominate whats collectively known as the Virgo Supercluster of galaxies, which all lie within 100
million light years of the Milky Way. The Local Group is shown in the center.
Credit: ESO
There are exceptions; aside from the Andromeda galaxy, theres a remote
galaxy near the Big Dipper thats worth looking whatever size of telescope
you have access to.
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Fig. 10.6 Bodes Nebula (M81), the Cigar galaxy (M82) and galaxy NGC
2403 are all members of the M81 Group of galaxies, which also form part of
the Virgo Cluster
Visualize a line that goes from the bottom of the Big Dippers bowl to the
top, from Phecda to Dubhe, one of the pointer stars (Fig.10.6). Go the same
distance again in the same direction and youll come to the location of
M81, an oval-shaped galaxy bigger than the Milky Way. Try for it in binoculars firstits +6.8 magnitude then point your telescope (minimum
4-inch, though in a 10-inch it looks fantastic). Averted vision is needed to
get a sense of the brightness around the core, but to see something so
distant and galaxy-like is truly stunning. If you cant see it, stay up very
late, or make a note to look for it next spring when it will be higher in the
sky. Just above M81, also in the M81 Group, and in the same field of view in
binoculars is M82, the Cigar galaxy (which we see side-on, hence the
name), though at 8.4 magnitude its harder to see, especially if viewing
from an urban area. There are about 30 other members of the M81 Group,
of which another one, NGC 2403 (see below) is also easy to find.
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stars to look for in the night sky throughout the year. Double stars are now
known to be so common that when we refer to a star by name, were most
likely talking about a multiple star system rather than an individual star.
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large white star and a small, dimmer star with a hint of yellow. This is a true
binary star system around 115 light years from us; the two stars are 67AUs
apart, and orbit each other every 8300 years (Kaler 2015).
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us) and a blue star (HD 192579, over 1300 light years from us). Those
pointing a refractor (Chap. 9) telescope almost at the zenith will begin to
realize the disadvantage of having the eyepiece near the floor; you may
need a chair, or perhaps even a cushion (wrapped in a plastic bag to avoid
it getting wet) to kneel on to get a view.
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Fig. 10.7 Find the Dolphins Double star in Delphinus, then move to Enif to
locate globular cluster M15
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and is just 50 light years away (Kaler 2015). It takes just four days for
Bellerophon to orbit its star.
Many more planets have been found since, but 51 Pegasi b (Fig. 10.8)
remains one of the Search for Extra Terrestrial Intelligence (SETI) Institutes
top-five candidates for radio signals from intelligent civilizations. 51 Pegasi
also happens to be a star very similar to our Sun (Chap. 12).
Instagram theMoon
Astrophotographyusually using a telescope and a camera in
conjunctionis one of the most expensive and complex hobbies of all, but
its surprisingly easy to do at a basic level with any telescope or mounted
binoculars, and any smartphone or inexpensive compact camera.
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Astro-phoneography
With either a pair of binoculars on a tripod, or a telescope aimed at the Moon,
all you have to do is place a smartphones camera optics over the eyepiece. It
will need nudging until the Moon comes into view on the phones screen, but
its merely a matter of patience. Press the smartphones touchscreen to focus
on the Moon, and take a few test shots. Either process works just as well
using a compact camera.
Fig. 10.9 Just a smartphone was used to take this photograph of the Moon
through a 4-inch telescope. Jamie Carter
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Fig. 10.10 Instagram photo of crescent Moon with Earth-shine taken using
a smartphone and mounted binoculars. Jamie Carter
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Adding Accuracy
If astro-phoneography becomes a habit, there are various devices and
mounts that can help position your smartphone more accurately and reliably, though most of then are manufactured for specific models of phone,
binoculars and telescopes.
References
Consolmagno, Guy & Davis, Dan M.Turn Left at Orion: 4th Edition. Cambridge
University Press, Cambridge. 2011.
Kaler, Jim. Stars. [ONLINE] Available at: http://stars.astro.illinois.edu/sow/sowlist.html. [Accessed 01 June 15] 2015.
NASA.NASAs Hubble Shows Milky Way is Destined for Head-On Collision. [ONLINE] Available at: http://www.nasa.gov. [Accessed 02 June 15]. 2013.
NASA. The nearest super-clusters. [ONLINE] Available at: http://heasarc.nasa.
gov. [Accessed 02 June 15]. 2004.
Vardanyan, M., Trotta, R., Silk, J.Applications Of Bayesian Model Averaging To
The Curvature And Size Of The Universe. Monthly Notices of the Royal Astronomical Society. Wiley. 2011.
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A Mess ofMeteors
As temperatures drop in the northern hemisphere, the appeal of yet
more minor meteor showers might be on the wane. However, theres a
good chance that any hour-long stargazing session in November will
herald a fireball or two. The first half of the month see the South Taurids
and the North Taurids offer a handful of shooting stars from the direction
of Taurus; handy if youre planning to watch the stars of winter return to
the night sky. Peaking later in the month are the Leonids, which radiate
from Leo below the northern horizon and promise around ten per hour.
Check astronomical calendars and websites for the exact peak dates,
though the later at night you stargaze, the more shooting stars youll
likely see.
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Return tothePleiades
Now high in the sky again is one of the jewels of the night sky, but pointing
a telescope at the Pleiades has an unexpected effect.
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that area. While it sparkles in binoculars, the bustle of the Pleiades is lost
in a telescope. It just looks straight through it. Its a lesson in why a
telescope isnt always the best option, however much it costs, but there
are reasons to put magnification on the Pleiades. If you have a large telescope, you may spot some of the bright nebulosity between these huge,
hot, 100 million years-young stars, which are illuminating an interstellar
cloud of gas and dust the cluster is moving through. Even with a small
telescope you should be able to see some double stars that binoculars
cant reach.
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Fig. 11.2 Inside the Pleiades are the other Seven Sisters (though only five
are visible in this photograph) and a nice double star, Burnham 536 Credit:
NASA/ESA/AURA/Caltech
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Fig. 11.3 The Fall Triangle & Perseus, which has dozens of stargazing
targets including the Double Cluster, M34, Melotte 20 and an eclipsing
binary star system called Algol
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in our own galaxy that if two star clusters are thought to be the same distance from us, they probably have a common origin. Thats thought to be
the case with M34 (see above), which is roughly as far from the solar system
as the Pleiades, the Alpha Persei Moving Group/Melotte 20 in Perseus (see
above), the Stephenson 1 cluster at the center of Lyra, and the IC 2602 (also
called the Southern Pleiades) cluster (Chap. 13) and NGC 2516 clusters in
the southern hemisphere constellation of Carina (Chap. 13). The spatial
motion of all of these clusters means they could all originally be from the
same stellar nursery.
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A Home intheHeavens
Another circumpolar constellation, and high in the north-western sky in
November, Cepheus looks like a drawing of a house that a child might produce in pre-school.
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Fig. 11.4 Easily found from Cassiopeia, the constellation of Cepheus looks
like a house. Around it are three of the most distant stars, the Garnet Star,
Deneb & V762 Cass, and one of the biggest, VV Cephei A
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Fig. 11.5 Precession means that Errai will displace Polaris as the north star,
followed by Alderamin, Deneb, Vega, Theban and Kochab as part of a counter-clockwise 26,000-year cycle. The year that each of these stars will next
become the north star is shown in red. Credit: based on a chart on
Wikipedia - Tauolunga
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As well as being one of the most distant naked eye stars, the Garnet Star is
also one of the most luminous stars known at a staggering 600,000 times
brighter than the Sun. Its also 1600 times larger. However, even thats
topped by the equally distantand possibly relatedVV Cephei A in the
centre of Cepheus (Fig.11.4), a +4.9 magnitude star that is the biggest star
weve come across this year.
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Jupiter orbits the Sun every 12 years, so although it does dip into the lowest
part of the ecliptic (which is tricky to see from the northern hemisphere), its
most high in the sky and easy to see for months on end each year. By now
youll probably know exactly where Jupiter is, having tracked the progress
of this, one of the brightest objects of all, across the night sky since January.
If you dont, use a monthly updated star-chart or a phone app to check on
its specific position, because it wont appear on a planisphere.
Io
The most geologically active place in the solar system, Io has mountains
higher then Mount Everest and volcanic plumes that spew sulphur 300
miles up. This intense activity means that Io is the only object weve ever
observed that doesnt have impact craters.
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Europa
Roughly the size of our Moon, Europa is thought to have a liquid water ocean
below its thick icy crust, anduniquelyplate tectonics similar to that
found on Earth. In December 2013, the Hubble Space Telescope detected
water vapor above its south pole, and its suspected that it hosts more water
than on Earth. Should we send a probe? NASA thinks so, and wants help with
planning a low-budget mission to reach Europa. Since its probably had its
ocean for millions of years, Europe is the favorite for extra-terrestrial life.
Ganymede
In your telescope Ganymede will look the brightest of all of Jupiters
moons. Bigger than Mercury and Pluto, and three-quarters the size of Mars
[NASA 2015], Ganymede has its own magnetic fieldand thus hosts auroral displays, known to us on Earth as the Northern or Southern Lights
(Chap. 14). In studying those lights in 2015, the Hubble Space Telescope
found evidence of an ocean of water beneath its icy crust. In 2030, the
European Space Agencys JUICE (JUpiter ICy moons Explorer) probe will
arrive to take a closer look (as well as at Europa and Callisto).
Callisto
In a telescope, Callisto is the furthest and dimmest moon. A fraction
smaller than Mercury, Callisto is the most cratered celestial body ever studied. Its also suspected to have an underground liquid ocean, and because
its much further from Jupiter, it has far less radiation than Europa; a trip
here might prove much easier for humans.
Jupiters Surface
Those with a high power telescope should be able to make some of the key
features in the Jovian atmosphere, but even with a 4-inch telescope you
should be able to discern three or four distinct belts (Fig. 11.6). If youre
lucky (with both the size of your telescope and the timing), the famous
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Fig. 11.6 Jupiter with all four of the Galilean moons visible. Credit: Massey/
Neugent/Lowell Obs./NSF
Great Red Spot could be within your reach. However, most of us will get
something much more basic, but no less stunning; a super-bright planet
that moves quickly through the field of view. Unless youve got a tracking
telescope, youll have to adjust it often.
In comparison to the enormous hot Jupiters astronomers have found
orbiting other Milky Way stars, our own Jupiter is a cold Jupiter. Around 5.2
AU or 779 million km from the Sun, Jupiter is made of hydrogen and
heliumas stars arebut its far too small to be considered a failed star.
Aside from the Sun, Jupiter is our solar systems linchpin; its gravity
destroys asteroids, captures comets, and affects the orbits of everything in
the solar system. Its exceptionally powerful gravitational pull is also why is
has over 64 moonsthose four youve just seen are only the largest. The
fact that we have a planet as big as Jupiter so far from our star also appears
to be pretty rare.
Disappearing Moons
On their journey around Jupiter, the moons cross in front of or behind
Jupiter, or pass through its shadow, and thus will be hidden from sight, so
dont be surprised if you can see only three of the moons. Occasionally all
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of the moons are invisible, but thats very rare. Jovian moon-watching is a
definite hobby; charts are published in monthly astronomy magazines that
show you exactly what time to look for a transit of a moon across the face
of Jupiteran event that also causes a dark shadow to appear on the
planets surfacethough youll need a 16-inch telescope to see that kind
of detail. Its much easier to look for all four moons lining up on one side,
which happens relatively frequently.
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Power Play
Usually an additional purchase, but sometimes included with telescopes, a
Barlow lens boosts the power of an eyepiece, typically doubling it. If you
have eyepieces with focal lengths of 25mm and 10mm, a 2 Barlow lens
placed between the eyepiece and a telescopes focuser effectively doubles
the magnification, giving you the equivalent of 12.5 mm and 5 mm eyepieces (Fig.11.7).
If you have a 4-inch/102mm telescope with a 800mm focal length, a 2
Barlow lens will push your 25 mm from 32 to 64 magnification. Your
9mm eyepieces magnification will grow from 89 to 178. On a 10-inch
scope with a focal length of 1200mm and both 25mm and 10mm eyepieces, a 2 Barlow lens will get you from 48 to 96, and from 120 to a
whopping 240. Its also possible to buy a 3 Barlow lens.
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Double Trouble
Its the 5mm that will likely tempt you most, though there are caveats to
using a Barlow lens. While planets and the Moon are ripe for extra magnification, the Andromeda galaxy (Chap. 10) and other faint objects are not.
The images a Barlow lens produces is significantly dimmer and more difficult to focus than unadorned eyepieces normally manage. Also, dont
expect Jupiter to suddenly fill your telescopes field of view, or for the Great
Red Spot on Jupiters surface to come into sharp focus.
Use a low-power eyepiece to find your target, then gradually zoom-in,
finally placing a 2 Barlow lens beneath a high-power eyepiece. If youre
looking at a planet or the Moon, your target can easily race out of your field
of view while you swap between eyepieces, which is why a motorized telescope that can track objects is valuable. Just remember that more magnification isnt necessarily what every object in the night sky either requires
or can stand.
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eyepiece should do the trick, though you have to time this one right.
Mercury reaches its greatest elongation three times per year, or every four
months, though its visible for a few weeks either side. Check an astronomical calendar and make a note in your diary.
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Fig. 11.8 Major craters on the surface of the Moon. Credit: NASA/Bill Ingalls
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Fig. 11.9 A Moon filter can reduce the glare of the Moon, but so can wearing shades. Jamie Carter
References
Dunlop, Storm. Night Sky: Get to Know the Natural World. HarperCollins,
London. 2004.
Kaler, Jim. 2015. Stars. [ONLINE] Available at: http://stars.astro.illinois.edu/sow/
sowlist.html. [Accessed 01 June 15.]
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Use averted gaze and youll begin to see the luminosity that was so
obvious in binoculars; that light is gas and dust being illuminated by stars
within it. Eventually, M42 will become a star cluster like the Pleiades, the
Hyades and the Beehive.
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Fig. 12.3 The constellation of Orion rising in December, with Lepus below.
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Fig. 12.4 Seasonal favorites this month include the Struve 747 double star
and three open clusters; Collinder 65, Collinder 70 and NGC 2264, the
Christmas Tree cluster. The positions of the Horsehead, Flame and Crab
nebulas are also indicated
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Bigger Binoculars
While a pair of 10 42 or 10 50 binoculars are great all-rounders and perfect for travel, if youre a big fan of using two eyes over one, some more
magnification is tempting. As you up the magnification, the aperture has
to rise, too, which means a bigger product thats neither as portable (big
binoculars no longer fit easily into carry-on luggage, for example) nor as
easy to hold steady; as a rule of thumb, anything larger than 10 50 should
be mounted on a tripod. Common specifications here include 15 70,
20 80 and 25 100 (Chap. 4), all of which will provide a tighter field of
view and more of a close-up. Instead of concentrating on the center of the
field of view in a pair of 10 42 or 10 50 binoculars, that same object
viewed through a pair of big binoculars suddenly fills the field of view and
becomes easier to study.
Fig. 12.5 Hubbles most famous photos, the Horsehead Nebula (top), Crab
Nebula (lower right) and the Pillars of Creation (lower left). Credits:
Horsehead NebulaNASA, ESA & Hubble Heritage Team (AURA/STScI),
Crab NebulaNASA/ESA/J. Hester and A. Loll (Arizona State Univ.) and
Pillars of CreationNASA, ESA/Hubble and the Hubble Heritage Team
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Fig. 12.6 Canon image stabilized binoculars are expensive, but offer a very
steady view of the stars. Credit: Canon
Mounting Binoculars
Since the unsteady view you get through your current binoculars will only
get worse if you use a higher magnification, big binoculars are best used
mounted on a tripod. Various brackets are available, but try to buy a pair of
big binoculars that has a screw thread for a tripod. Quicker to set-up than
a telescope, and more portable and cheaper, a pair of mounted binoculars
is much favored by experienced stargazers (Fig. 12.6).
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from hand-holding them. Even just trying-out a pair and comparing them
to a normal pair of binoculars will make you realize how unsteady you are!
There are only two downsides to this clever system; its battery driven,
which makes the binoculars heavier than most, and they cost an awful lot
of money (a pair of Canon 10 42 L IS WP binoculars were going for
US$1250 at the time of writing). If you can afford to spend that much,
I highly recommend them; as well as getting a steadier view of clusters, its
much easier to split double stars. Mostly they come in smaller sizes, though
the largest size available is 15 50, which is a big (and heavy) pair of binoculars. All are waterproof, so dewfall is not a problem if you stay out late
at night.
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elongated Big Dipper) and a faint 7 below it. These stars are about 3600
light years away. Its just possible to find the 3 with 10 50 binoculars,
though only if youve visited NGC 2169 before.
The Twins
Its position close to Orion means Gemini (Chap. 3) is a constellation thats often
ignored. Not only is its major open cluster, M35, worth a second look as Gemini
rises from the east this month, but one of its brightest stars is masquerading
not as a binary system, but something even more spectacular and strange.
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Fig. 12.7 Castor, the double-double-double star in our midst, with M35
and NGC 2169 close by in Orion
eye stargazers Castor (Fig. 12.7) plays second fiddle to the constellations
brightest star, Pollux. However, Castoronly around 50 light years
distantis actually three pairs of binary stars. Point any size of telescope
using a high-power eyepiece at Castor and you can split it into its two
bright, white stars, Castor A and Castor B, which orbit a common point. In
a 6-inch or bigger telescope you might even see a third, Castor C, close-by,
though its very faint. A and B orbit each other every 445 years, while C
takes 1400 years to make the journey around them. Although stargazers
can see no more detail, each of these three stars is actually a binary system
itself, making a total of six stars all gravitationally-bound to each other.
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When its at its highest in the evening sky, and so furthest from the Sun from
our perspectiveits maximum elongationVenus is a dazzling naked eye
sight, but in a telescope its bright, white and featureless. However, when its
between Earth and the Sunsomething called inferior conjunction (the
New Moon is said to be in a conjunction with the Sun)its possible to see
a crescent Venus (Fig. 7.7), though only in close-up through a telescope.
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Fig. 12.8 Two open clusters around Cassiopeia, M52 and NGC 7789, and
Achird, a G-type yellow dwarf star similar to the Sun
Visualize a line from Shedar to Caph in Cassiopeia, and keep going for the
same distance again (Fig. 12.8). In both binoculars and a small telescope
you should notice a yellow star on the western side that contrasts with the
blue-white the others (Tonkin 2014) in a dense but hazy field of view.
Larger telescopes will reveal around 30 stars.
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Sun-Like Stars
Although most of the stars easily visible in the night sky are bigger and
brighter than our Sun (Chap. 8), there are some that are much the same.
One of the best examples of a G-type star thats almost identical to the Sun
is Achird in Cassiopeia (Fig. 12.8). Two other examples of G-type yellow
dwarf stars include the closest star system to us, Alpha Centauri (Chap. 13)
at 4.3 light years and 51 Pegasi (Chap. 10) at around 51 light years.
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Table 12.1
Star/Age
Sirius in Canis Major (238 million years)a
Rigel in Orion (10 million years)b
Aldebaran in Taurus (3.2 billion years)b
Capella in Auriga (500 million years old)c
Castor and Pollux in Gemini (370 million years and 700 million years)d
Procyon in Canis Minor (1.7 billion years)e
a
Holberg (2007)
Kaler (2013)
c
Kaler (2009)
d
Schaaf (2008) and SolStation (2011)
e
Schaaf (2008)
b
park ages beside them, and youll take a fresh new look at some of the stars
you thought you knew so well. As you can see, the odd ones out this time
are clearly Aldebaran and Procyon, both of which are vastly older than the
others in the Winter Circle. However, it also underlines exactly how old our
Sun is; at 4.5 billion years, its been around far longer than most of the visible stars in the night sky.
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How to Find
Polaris
Double Star
in the Big
Dipper
Orions Belt
Best seen
with
Binoculars
Naked eye
Naked eye
and
binoculars
Telescope
Naked eye
and
binoculars
(continued)
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Best seen
with
Orion Nebula
Binoculars
Great Square of
Pegasus
The Andromeda
Galaxy
Naked eye
Naked eye
Naked eye
Telescope
299
www.google.co.uk/moon
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Fig 12.9 The landing sites for the first and last Moon landings, Apollo 11 &
Apollo 17. Credit: Massey/Neugent/Levine/Lowell Observatory/NSF
301
References
Consolmagno, Guy & Davis, Dan M. Turn Left at Orion: 4th Edition. Cambridge
University Press, Cambridge. 2011.
Holberg, J.B. Sirius: Brightest Diamond in the Night Sky. Springer Science &
Business Media, Berlin Heidelberg New York. 2007.
Kaler, James B. First Magnitude: A Book of the Bright Sky. World Scientific Publishing, Singapore. 2013.
Kaler, Jim. Stars. [ONLINE] Available at: http://stars.astro.illinois.edu/sow/
sowlist.html. [Accessed 01 June 15]. 2009.
Kaler, Jim. Stars. [ONLINE] Available at: http://stars.astro.illinois.edu/sow/
sowlist.html. [Accessed 01 June 15]. 2015.
Mollise, Rod. The Urban Astronomers Guide: A Walking Tour of the Cosmos for
City Sky Watchers. Springer-Verlag, London. 2006.
Rao, Joe. Great Star of the South. [ONLINE] Available at: http://www.space.com.
[Accessed 02 June 15]. 2005.
Schaaf, Fred. The Brightest Stars: Discovering the Universe through the Skys
Most Brilliant Stars. John Wiley & Sons, New Jersey. 2008.
SolStation Pollux. [ONLINE] Available at: http://www.solstation.com. [Accessed
05 June 15]. 2011.
Tonkin, Stephen. Binocular Astronomy, Second Edition. Springer New York
Heidelberg Dordrecht London. 2014.
Tonkin, Stephen. The Christmas Tree Cluster, Binocular Tour. BBC Sky At Night
magazine January 2015, Immediate Media, Bristol. 2015.
PART IV
Upside-Down Stargazing
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CHAPTER 13
UPSIDE-DOWN STARGAZING
The Southern Sky
Head south and the sky is upside-down. Confusing, baffling and yet surprising and spectacular, stargazing in the southern hemisphere is like
meeting a long lost sibling, or reading a newly discovered book by your
favorite author.
If you live in the northern hemisphere, any experience with the a southern
sky is likely to be fleeting, most likely on vacation in Australia, South Africa
or South America.
I spent an entire year in Australia when I was in my mid-twenties. I wasnt a
stargazer back then, and in my time in the vast country I looked at the
night sky properly only once while camping out in a bivvy bag near Uluru,
or Ayers Rock, in the countrys Red Center. It was a real blanket of stars
moment, and on that Moon-less night I remember feeling completely disorientated. I recognized nothing. My regret is that I didnt ask why that was.
Celestial Set-Pieces
Its only over a decade later that I know what I was missing. The southern
hemisphere is a stargazers dream destination. It does have dark skies
some of the darkest on the planetand many high altitude areas, too,
though that doesnt fully explain why almost all of the worlds biggest and
best telescopes are built south of the equator.
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The reason is that from places like South Africa, Argentina, Chile, Australia,
Fiji and New Zealand its possible to see some of the night skys most
intriguing sights.
Why is the southern hemisphere the only place to be for astronomers?
Simple: while the North Pole faces outwards to the Universe beyond, the
South Pole points to the galactic center of the Milky Way. That has obvious
consequences for stargazing; there are billions of stars, and more bright
stars, more constellations containing more objects in the southern skies.
Whats more, theyre circumpolarthey rarely set. Its a celestial set-piece
that stargazers find hard to resist.
Upside-Down Stargazing
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http://skymaps.com
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Fig. 13.1 To travelers from the northern hemisphere, the Moon looks
upside-down from southern latitudes, such as here in the Atacama Desert
in Chile. Credit: ESO/Sergio Otarola
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Fig. 13.2 The southern sky seems familiar yet strange to visitors from the
northern hemisphere; find the upside-down Summer Triangle and it will
lead you to the Teapot, with Alpha Centauri and the Southern Cross in the
south-west (JulySeptember)
The best time to see the Great Rift is between July and September, when
the Milky Way stretches overhead.
Upside-Down Stargazing
311
sky (Fig. 13.2). Also known as Rigil Kent, its 4.3 light-years from Earth. Its
actually a double star itself, made from two Sun-like stars, though together
with tiny Proxima Centauri, Alpha Centauri is a triple star system.
If you live below about 25 degrees north, you might see Alpha Centauri peek
above the southern horizon; it was worshipped by the Egyptians, who
erected temples at Corinth and Delphi with special alignment to the rising of
this star (MuseumVictoria 2013). To watch Alpha Centauri and ponder
whether humans might one day visit this star system is a special treat when
traveling to the southern hemisphere. However, it would take tens of thousands of years to reach Alpha Centauri or Proxima Centauri on current rocket
technology. Its probably best we wait for a technological breakthrough
before contemplating a trip, but navigating home would be easy; in Alpha
Centauris night sky our Sun would appear as a bright star close to Cassiopeia.
Fig. 13.3 In this busy area of the southern hemisphere sky are the Southern
Pointers, the Southern Cross, the False Cross, the Jewel Box cluster, the
Coalsack Nebula and the Eta Carinae Nebula
Fig. 13.4 The Southern Cross and Alpha Centauri straddling the Milky Way
is an arresting southern hemisphere sight. Credit: ESA & A.Fujii
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Fig. 13.5 The Jewel Box cluster as seen by the ESO Very Large Telescope
(VLT) at ESOs Paranal Observatory in Chile. Credit: ESO/Y.Beletsky
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Fig. 13.6 How to find the south celestial pole in winter (top) and summer
(bottom)
Upside-Down Stargazing
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Canopus can easily be found from October through May high in the southern sky (Fig.13.6). For most of that time its joined by Sirius.
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Fig. 13.7 The Small and Large Magellanic Clouds soar high above Cerro
Paranal and the VLT in Chile. Credit: ESO/B.Tafreshi (twanight.org)
who spotted them in 1519 while circumnavigating the globe for the first
time. Although theyre both circumpolar, theyre best seen when highest in
the sky on a dark, Moon-less night between September and April (Fig.13.9).
The LMC contains the Tarantula Nebula, which is best thought of as a
super-massive version of the Orion Nebula (Chap. 4). One hundred times
larger, this is the biggest star-forming region in our part of the Universe,
and so luminous that if it was as close to us as the Orion Nebula is (about
1300 light years), it would cast a shadow on Earth at night (NASA 2012).
Fig. 13.9 The Small and Large Magellanic Clouds, 47 Tucanae, Fornax,
Canopus and the location of the space probe Voyager 2in the constellation
of Pavo (SeptemberApril)
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but its noticeably brighter in the centerwow! Its impressive, but this is
one to get some magnification on; in a telescope its like cracking open a
geode and finding it filled with gold dust (OMeara 2013) (Fig.13.8). Its on
the opposite side of the SMC to the LMC (Fig. 13.9). 47 Tucanae is 13,400
light years distant and about 10.5 billion years old.
Upside-Down Stargazing
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Fig. 13.10 The Hubble eXtreme Deep Field photograph of 2012 contains a
dumb-founding 5500 galaxies, and was taken within the constellation of
Fornax. Credit: NASA; ESA; G.Illingworth, D.Magee, and P.Oesch, University
of California, Santa Cruz; R.Bouwens, Leiden University; and the HUDF09
Team
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Fig. 13.11 Globular cluster Omega Centauri and Centaurus A galaxy can be
seen near the Southern Cross
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If you range your binoculars below the plane of the Milky Way youll likely
spot a beautiful open cluster around 479 light years away called the
Southern Pleiades (Fig. 13.3). Look for a bright star in the center and four
others around it arranged as cardinal points; a classic binocular sight.
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References
Jet Propulsion Laboratory (JPL). Where are the Voyagers? [ONLINE] Available
at:http://voyager.jpl.nasa.gov/where. [Accessed 02 June 15]. 2015.
Museum Victoria. Sky Tour for Binoculars: Crux & Centaurus. [ONLINE] Available
at:http://museumvictoria.com.au. [Accessed 02 June 15]. 2013.
NASA. Hubbles Close Encounter with the Tarantula. [ONLINE] Available at:
http://www.nasa.gov. [Accessed 02 June 15]. 2012.
OMeara, Stephen James. Deep-Sky Companions: Southern Gems. Cambridge
University Press, NewYork. 2013.
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CHAPTER 14
ECLIPSES ANDAURORAS
Stargazing Without theStars
There are rare and spectacular celestial phenomena that have little to do
with constellations and stars. Perhaps the most famous is a solar eclipse,
when the Moons shadow races across a narrow band of the Earths surface.
Those below experience a blackout and see a hole in the sky (Fig. 14.1).
A lunar eclipse is viewable from far larger areas. Its much more subtle, but
a copper colored Moon is a beautiful sight. Lastly comes the aurora,
spectacular seasonal displays of magnetic activity. Pulsing greens curtains
dance around the poles in whats known in the northern hemisphere as the
Northern Lights. See all of these phenomena and youve achieved a
celestial hat-trick.
What Is anEclipse?
There are two different types of eclipse, solar and lunar. A solar eclipse
occurs when the Moon passes in front of the Sun, and a lunar eclipse when
the Moon passes into Earths shadow.
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Fig. 14.1 A totally eclipsed Sun from the Faroe Islands, March 20, 2015.
Credit: Nick Glover
when a Full Moon crosses the ecliptic. Both events are rare, but predictable
down to the second.
Since the Moons shadow on Earth is small, few people get to see an
eclipsed Sun. Since the shadow Earth projects into space is huge, anyone
on the night-side of the planet can at least see part of a lunar eclipse.
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Thats not the case with a total solar eclipse, which is a fluke of celestial
alignment. The mechanics are such that to us on Earth the Moon and Sun
often appear to be exactly the same size. The Sun is 400 times larger in
diameter than the Moon, but 400 times further away. The match-up is exact
and, for a brief time, the Moon completely covers the Sun. At this point
there is a blackout and its possible to see the Suns mighty corona. This is
called totality.
Solar Eclipses
A total eclipse of the Sun is one of the most visually and even emotionally
spectacular natural events anyone could hope to see. Those who have yet
to see the Moon block out the Sun for a few precious minutes may doubt
that assertion, but the event gives such a powerful sense of the tremendous depth of the solar system that every stargazer should try to catch a
total solar eclipse.
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Fig. 14.2 A partially eclipsed Sun is a beautiful sight, but dangerous to look
at without solar safety glasses. Credit: NASA/Bill Ingalls
A partial eclipse is potentially dangerous to observe. Its not possible to
look at the Sun with a bite taken out of it unless youre wearing special
solar safety eclipse glasses. Some light cloud can offer a brief glasses-free
glimpse of the event, but never view a clear partial solar eclipse with the
naked eye.
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Fig. 14.3 A total solar eclipse above the Faroe Islands, March 20, 2015.
Credit: Visit Faroe Islands/Bardur Eklund
Youll need to be on a very narrow track on the Earths surface (known as
the line of totality) to witness a total solar eclipse, but its worth crossing
continents for.
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First Contact
The spectacle begins with a long partial eclipse phase lasting around an
hour. The edge of the Moon appears to touch the Sun, and take a bite that
gets bigger while the light fades; youll need solar filter glasses to see this
safely. A slotted spoon or a colander is also handy. With some blank card in
one hand, hold up the spoon or colander above it at arms length to get tiny
crescent Suns projected onto the card (Fig.14.5).
Bailys Beads
About 10 seconds before and after totality, beads of the only remaining
visible sunlight pour through the valleys of the Moon. Just before the Sun
is completely blocked, the last rays create a magical Diamond Ring around
the Moon that signals the start of totality. Only now can you take off your
solar safety glasses (Fig.14.4).
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Fig. 14.4 Even during a total solar eclipse, solar safety glasses are essential
for all but totality Jamie Carter
Second Contact
As the two celestial bodies line-up, an eery light falls on those standing
under the growing Moon shadow. Light levels start to dwindle until the
strangest silvery twilight overtakes everything but the horizon, which
remains brightly lit.
Totality
After Bailys Beads have finished dancing on the Moons edge all sunlight
ceases and the corona suddenly flashes into view. Theres a hole in the sky,
a truly spectacular sight. Many think the Sun is yellow, but those whove
stood under the shadow of the Moon during a total solar eclipse know different. The corona appears as bright, white ribbons billowing in a breeze.
This is the time to pick up your binoculars and look around the edges for
bright red prominences, huge solar flares and explosions on the surface of
the Sun (Fig.14.6).
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Fig. 14.5 During a partial eclipse, crescent Suns can be projected onto card
through a colander Gill Carter
During totality dont forget to look for planets, if there are any nearby. Plan
ahead by looking at a stargazing app. Though the Suns corona is an intoxicating and preciously short sight, its also worth having a brief look around you at
the different colors, the eeriness and the effect of the eclipse on the sky behind
you (as well as on the people around you most fall utterly silent in awe).
With the Sun blocked for a few minutes, there can also be a drop in temperature. There is a slight lag, but if youre somewhere particularly hot or
humid, the temperature change can be dramatic (Fig.14.6).
Third Contact
As the Moon moves away from the Sun, the entire spectacle goes into
reverse. Baileys Beads appear on the opposite side until theres a powerful
flash of yellow or even pink light from the emerging Sun, and the famed
Diamond Ring; Third Contact is achieved. Totality is over, and the solar
safety glasses must go back on.
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Fig. 14.6 Solar flares and prominences can be seen during totality. Credit:
Nick Glover
Fourth Contact
From the end of totality until Fourth Contact, when the two bodies drift
apart, theres another long partial eclipse. At this point totality junkies
begin to drift off, having seen what they came for. Thats a shame because
a partial eclipse is a spectacular and rare event in its own right, and
demands to be observed.
Totality or Bust!
A total solar eclipse is far more impressive a partial eclipse. The difference
between watching a 99% eclipsed Sun and a totally eclipsed Sun is huge.
It all happens within the last 15 seconds when the sun goes from 99.9%
covered to 100% coveredand its that 0.1% that makes all the difference.
Its that exact match-up between Moon and Sun that enables us to stare at
the Suns corona.
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Eclipse-Chasing
To eclipse means to obscure, and some would use that word to describe the
hobby of chasing the shadow of the Moon around the world. Hordes of
eclipse-chasers hooked on this once-in-a-lifetime spectacle are determined to make it anything but. Many eclipse-chasers meet-up once a year
or so in random parts of the globe just to witness a solar eclipse, and they
often rack-up dozens of experiences. If the Moon-shadow is due to make
land in a very specific areasuch as over some small islandsa total solar
eclipse can feel like a festival or a major sports event.
A solar eclipse is hectic, it lasts just a few minutes. Its blink-andyouve-missed-it stuff, and whether the inevitable clouds clear in time for
totality can make it a stressful experience. It demands good research and
preparation, and the ability to cope well with extreme disappointment. So
stargazers make perfect eclipse-chasers!
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appear very small, but its a neat way of getting a souvenir shot while also
witnessing the event with your own eyes and emotions. Youll still need a
tripod. Its also important to lock the exposure level to capture the changes
in brightness (otherwise your camera will simply compensate for the lack
of light and ruin the effect).
Either way, if you are going to photograph an eclipse, avoid crowds if you
can; your tripod will get kicked, and people will likely walk in front of your
camera.
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Fig. 14.7 Its possible to photograph a partially eclipsed Sun through cloud
using just a smartphone and some mounted binoculars Jamie Carter
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August 12,
2026
August 2, 2027
July 22, 2028
breaks down; the town of Carbondale, Illinois in the USA will experience
two blackouts in just seven years. Not only will the USA experience a total
solar eclipse on August 21, 2017, but another will sweep through on April
8, 2024. While totality lasts just two minutes in 2017, its over four minutes
seven years later. Both eclipses have completely different paths, but they
intersect near the Illinois, Missouri and Kentucky state border. Given that
the last total solar eclipse in the USA was in 1979, these two events so close
together represent something of a celestial jackpot.
Lunar Eclipses
By now you should have spotted Earth-shine on the Moon (Chap. 3), and
you also know when to see a Moon-shadow. You can complete the set by
finding an Earth-shadow on the Moon.
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Fig. 14.8 These sequential photos show the Moon entering the Earths
penumbral shadow bottom-left and exiting its umbral shadow top-right.
Credit: NASA
A total lunar eclipse is not as special as a total solar eclipse, but it is a much
longer spectacle. Instead of one moment of wonder, totality during a lunar
eclipse can last for well over an hour, while the Moon can take over five
hours to enter and exit the Earths shadow fully (Fig. 14.8). Its a subtle
rather than spectacular sight, but beautiful nonetheless.
A lunar eclipse can only happen at Full Moon, when our satellite is at its
dazzling brightest, but during the eclipse it doesnt just lose its illumination. Earth prevents the Suns light from directly hitting the Moon,
but some sunlight refracted through the Earths atmosphere gives the
lunar surface a dull, reddish orange or copper color. Its often called a
Blood Moon, though thats a massive exaggeration. The science at play
is the same as the reddening of a rising and setting Sun. No two lunar
eclipses are identical, which make them very special events for
Moon-watchers.
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Fig. 14.9 As the Moon enters the Earths umbral shadow there is the odd
sight of its disk half-illuminated, but with no sharply-defined terminator.
Credit: NASA
theres a subtly curved, though fuzzy line dividing the un-lit and lit portions
of the Moon. What youre seeing, rather incredibly, is the outline of the
Earth on the Moon (Fig.14.9).
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Table 14.2 Total Lunar Eclipses 20182030a (Locations given are for the
total lunar eclipse phases; a partial lunar eclipse is visible for many more
locations either side.)
Date
Viewing locations
January 31, 2018
July 27, 2018
January 21, 2019
May 26, 2021
May 16, 2022
November 8, 2022
March 14, 2025
September 7, 2025
March 3, 2026
December 31, 2028
June 26, 2029
December 20, 2029
a
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ways. Aurora bands streaking across a clear night sky is most definitely one
of stargazings most intoxicating sights.
They may have little to do with stars and planets, but the aurora are a visible link to whats happening on the surface the Sun.
Silent Storms
When electrically charged particles from solar flares on the Suns surface
collide with atoms in the Earths atmosphere, the result is often a light
show of aurora around the planets magnetic poles.
Most displays of aurora appear from the north (if in the northern hemisphere)
as a faint green glow, which aurora hunters call a forest fire (Fig. 14.11). On
some nights, thats the peak of the displays. On other nights, the aurora
spread overhead (Fig.14.12) and an auroral storm consisting of curtains, arcs,
swirls and streamers commences, and can last up to an hour. Within this silent
Fig. 14.11 Aurora are best used as a backdrop in photos. Jamie Carter
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Fig. 14.12 Magnetic auroral storms can appear suddenly and unpredictably.
Jamie Carter
storm there can be several distinct peaks and troughs of auroral activity. All of
a sudden it will cease, with only faint shimmers visible in the distance until
they fade from view. Though most auroral displays are green, its also possible
to see pinks, reds, browns, yellows and even blues.
The displays of aurora around the north pole and the south pole are identical. Dependent on exactly the same excess of particles from the Sun, the
aurora borealis (Northern Lights) and aurora australis (Southern Lights) are
almost a mirror image.
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Not so the aurora borealis, for which you need to be under the auroral oval
around the north pole. It waxes and wanes in size, but is centered on the
Arctic Circle between latitudes of about 6572 degrees North. Finland,
Iceland, Norway, Sweden, Greenland, Iceland, Alaska, Northern Canada
and Siberia all frequently see the aurora borealis. Since these areas have
long, dark winter days (and very long summer days), peak viewing time for
the aurora borealis is November through March.
Observing Tips
Get yourself somewhere away from light pollution (avoiding a Full Moon)
and be patient. Those around the Arctic Circle often see aurora borealis
directly above them, but if youre further south, look to the northern horizon. Wherever you are, the top of a nearby mountain that doesnt overlook
a town or city to the north, or somewhere with a wide-open northern
horizon, is a good choice.
Though youre likely to be stargazing while you wait, a cafe or somewhere
warm to retreat to nearby helps because you may have to wait a few hours.
Also remember that even if there are strong displays of aurorae, if its
cloudy or raining youll see nothing. Aurora viewing means being outside
late at night in temperatures well below freezing, so dress appropriately.
Magnetic Midnight
Experienced aurora-hunters can predict when displays may happen.
Though it does pay to have someone in the know leading your search for
aurora, the rule of thumb is simple; an hour either side of magnetic midnight. If youve not seen any aurora by 1 am, its probably not going to
happen. Thats a bit of a relief if youre in freezing temperatures.
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Photographing Aurora
With a DSLR camera, some simple techniques and some good luck, its
possible to get great photos of the aurora. Forget smartphone cameras,
theyre not sensitive enough.
Another great reason for taking photos of aurora is that a camera is much
more sensitive and will pick-up traces of green and other colors that might
be invisible to your eyes.
Ideally use a wide-angle 1020mm lens with fast aperture of between F1.4
and F3.5 to get as much of the sky and foreground in the shot as possible.
Makes sure your lenses are clean, and remove any filters you might be
using during the day. As for all night sky photography, a tripod is mandatory because you may need to open the shutter for as much as 30 seconds.
Use a remote shutter release cable, or set a two second delay on the shutter
release to get sharp images. Ramp-up the ISO to 1600 and experiment with
shutter speeds from four seconds to a maximum of 25 seconds. The results
will astound you and, as a bonus, you might get stars (Fig.14.13).
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The biggest mistake most people make is that they dont know their
cameras well enough to quickly change settings in the dark and cold. Its
therefore a great idea to prepare in advance; switch-off the lights at home
and spend time in darkness changing the shutter speed, the aperture and
the ISO on your camera until it becomes second nature. The aurora waits
for no-one, and a spectacular display can come and go while youre facedown in your camera trying to change settings. If you know your camera
and its set-up well, you can frame a shot, open the shutter and get back to
enjoying the show.
However, composition is everything if youre to avoid photos that look like
little more than green clouds. Use the aurora as a backdrop, not the subject
of a photo, perhaps using the top of a hill, fell or mountain, a house, a lone
tree or a forest, or a river or lake for reflections (Fig.14.14).
As with all outdoor photography expeditions, bring plenty of SD cards, a red
head-flashlight and a spare camera battery or two kept close to your body.
It will likely be too cold for fingerless gloves, but thin gloves that enable you
to operate the camera are essential. Wear thick mittens over the top.
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Fig. 14.14 An object in the foreground helps improve photos of the aurora,
though patience is required. Jamie Carter
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Fig. 15.1 Europe, the USA and Japan seem ablaze on this night view of the
globe, but there are precious dark spots within. Credit: NASA Earth
Observatory image by Robert Simmon, using Suomi NPP VIIRS data provided courtesy of Chris Elvidge (NOAA National Geophysical Data Centre)
Fig. 15.2 Its becoming increasingly necessary to travel to find truly dark
skies. Credit: ESO/S.Brunier
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somewhere away from the city where +6 magnitude stars can be seen, the
difference will amaze you. Theres so much more to see.
Things completely out of your control can ruin even a Class 1-rated dark
sky site; snow is hugely reflective and amplifies light pollution intensely,
while car headlights can dazzle you in an instant. The presence of a bright
Moon also renders any dark sky comparisons pointless.
Gaining Altitude
There is, however, an easy way to cheat the Bortle Dark-Sky Scale; head
upwards. Altitude can really bring out the clarity of the night sky, and when
stargazing from a high mountain zone a Class 4 site can easily become a
Class 3. The tell-tale is planets; at altitude a bright Jupiter or Venus can
become almost as distracting as the Moon.
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What toPack
Transporting a telescope across the world isnt practical. Amateur
astronomers on dedicated dark sky trips will often pack tripods, finderscopes, a couple of cameras and more besides. The majority of stargazers will visit a dark sky zone as part of a longer trip, especially if its a
long-haul destination, so traveling light is essential. Its also perfectly
possible; pack only a pair of 10 42 or 10 50 binoculars, which fit nicely
into a cabin-sized backpack. Also in your bag should be a printed starchart, a flashlight with a red light mode and (perhaps most importantly
of all) an observing list or a detailed idea of what you want to see and do
when you get under the untainted night sky you may have traveled far
to experience. Where youre going, what optical equipment youll
encounter, and who youll be stargazing with will help decide that.
Hopefully this book will also help you select some seasonal sights wherever in the world you visit.
Visiting Observatories
With well-equipped observatories dotted around the worlds dark spots,
theres little need to travel with a telescope.
Even if youve a big telescope at home, youll not have anything
approaching the size and quality of the gear regularly found at professional or even public observatories. Many of the worlds very biggest
telescopes responsible for the latest astronomical research are often
robotic, unmanned and situated on remote mountainsides in Chile,
Hawaii and South Africa, but they often dont want visitors. However,
dotted around the globe are dozens of observatories committed to public outreach, small private observatories, stargazing-friendly hotels, and
even campsites with telescopes. All offer superb night sky experiences.
From guided stargazing and night walks to lectures and sessions with
powerful telescopes, there are dozens of ways of interacting with both
local people and the night sky in most of the worlds greatest dark sky
destinations.
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Deep Time
The Grand Canyon represents deep time to rival anything visible in the
night sky. With the naked eye we can see 2.5 million light years into history
when we stargaze at the Andromeda galaxy (Chap. 10). The oldest of the 40
or so sedimentary rock layers visible at the Grand Canyon are a staggering
two billion years old.
Geologists have come here since it was first protected in the 1890s, but
now stargazers are flocking to this must-see national park for its lack of
light pollution. Were star ting to see more and more people tell us that
theyre coming to the Grand Canyon for its night skies, says Ty Karlovitz,
a Ranger who works in the interpretation division at Grand Canyon
National Park, as we stand beside the south rim of the canyon at an altitude of 6,800ft. The Grand Canyons night skies are one of my favorite
parts of the job.
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However, Grand Canyons popularity with stargazers has a lot to do with its
location, its accessibility, and its altitude. Weve got a high elevation, dry
desert air, and really clear night skies, says Ty, who tells me that the second
half of September until mid-November is reliably clear. In the early
summer until early fall we have a dryer climate with no winter storms or
summer rains, just crystal clear night skies. Theres also about a million
acres to stargaze from.
June brings the parks annual Grand Canyon Star Party; for eight days,
amateur astronomers come from Tucson Amateur Astronomy Association
and Lowell Observatory in Flagstaff to set-up telescopes behind the visitors center for anyone to use, compete with talks, constellation tours and
guided stargazing. On the north rim, the Saguaro Astronomy Club of
Phoenix follows suit.
Light Pollution
This national park hasnt yet become a well known dark sky destination
because there is some light pollution in Grand Canyon Village where most
of the five million annual visitors either visit or stay. The park authorities
are about to embark on a project to make lights more night sky-friendly.
The park does have a little light pollution, but were working towards
becoming an official Dark Sky Park, says Ty. Were now using nightfriendly colors for lights, like the softer oranges and reds, he says. Most of
the lighting is already angled down, and nothing is projected up into the
sky, though there is still work to be done in some of the main viewing areas
on the south rim. Were trying to make it better, but we have this natural
setting thats really goodeven in the Grand Canyon Village where the
light pollution level is highest I can walk out to the edge of the canyon and
look up and see a lot of really neat stuff.
Ty is right. During my chilly January visit I spotted Venus, and beside it tiny
Mercury just after sunset, followed an hour later by the Milky Way. It was
filling the sky near Perseus and Cassiopeia overhead, and tipping into the
vast Winter Circle asterism (Chap. 2).
To see that, and the Beehive Cluster as an easy naked eye sight, needs only
a short walk away from Grand Canyon Village down Bright Angel Trail.
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For now, that works OK, though there are distant threats to any future Dark
Sky Park status. We do get a little bit of light pollution from big cities, says
Ty. If you look way off to the west you can see a faint glow from Las Vegas,
but its not enough to really inhibit the viewing of the stars.
Different Stories
If you travel to dark sky destinations, soon enough you begin to leave
behind the constellations youve spent so much time learning. After all,
what use are Greek myths when youre in the remote deserts of the Wild
West? Im fascinated by the taking of the exact same group of stars to
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make a totally different story. It all depends on our perspective and our
backgrounds, says Ty, who recalls that while working in Honolulu National
Monument in Hawaii he learned that the W-shape that makes Cassiopeia is
known locally as the Chief Frigate Bird.
There have been humans in the Grand Canyon for 10,000 years, and in that
time a few stories have built up. Were all looking at the same constellations. When we look up and we see the Big Dipper and Cassiopeia, and the
north star, for the Navajo in the Grand Canyon that was one giant constellation, he says. The Big Dipper is Revolving Male, Cassiopeia is Revolving
Female, and Polaris is the central fire. These circumpolar constellations
represent the Navajo ideal; a husband and wife, with a cooking fire
between them (Fig.15.4). However, other Native Americans saw the same
stars of Revolving Male both as a bear (just as the ancient Arabs had with
Ursa Major) and as a skunk, its tail raised high behind it (Childrey 2004).
The skunk shape is particularly convincing; Ursa Major will never look the
same again!
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Navajo Constellations
Most of the Navajo stories tend to relate to the circumpolar constellations
and the winter stars. Orion is another ideal male figure, a young warrior, a
hunter and a provider, explains Ty. Like so many other cultures, they tie
that in with Scorpius, since the two are always opposite each other in the
sky. For the Navajo, Scorpius is basically the mother in law.
How ancient cultures used the stars to tell stories is called archeo-astronomy, a subject thats popular among stargazers and far less so among
astronomers. For Ty, its the main reason to gaze at the stars while he travels around this two billion year old park. The stars are just a neat way to go
back in time, he says.
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Prime Position
Tenerife is a favorite destination for stargazers after an unrivaled view of
one of the years finest night sights, the Perseids meteor shower, which
happens in mid-August every year (Chap. 8). Its also in prime position for
the equatorial constellations. Here, at a latitude of 28 degrees North of the
equator (which is about the same as Florida and Texas), its possible in summer to see constellations like Sagittarius, Scorpius and Libra much more
clearly than anywhere in Western Europe.
However, Tenerifes popularity with amateur astronomers had always perplexed me because the island attracts five million tourists every year. Sunseekers from all over Europe and beyond pile into the island year-round,
and its main tourist town of Los Christianos is a big light polluter. In fact,
coastal resort towns create an orangey glow that rings the island. How can
this be a good place for dark skies?
But it is. The key is the altitude of El Teide, a 12,198ft-high volcanic peak in
the very center of the island. This is the highest point not only in Tenerife,
but in all of Spain, and it rises from the vast Moon-like Parque Nacional del
Teide, which is itself 7,729ft above sea level. This UNESCO World Heritage
Site is beloved of stargazers. Crucially, its surrounded by an ancient caldera whose rocky ridges mostly block-out the light pollution from the
south and west of the island. To the north, the town of Puerto de la Cruz
can sometimes be glimpsed, but that coast is regularly covered by cloud.
Its precisely that cloud that blocks-out the light, and makes stargazing
from El Teide so reliably enthralling.
Sunrise Trek
Getting to the peak of El Teide isnt difficult. Hundreds of tourists drive the
hour so from the coastal resorts every single day to climb into the telerifico
cable car. It takes eight minutes to ascend to a viewing platform at a heady
11,663ft altitude, with an optional 30 minute hike up steep steps to the
summit. However, the last cable car back down leaves before 5pm. There is
only one way to see the stars from the mountain, and thats to spend
thenight.
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Fig. 15.5 At over 12,000ft up, the peak of El Teide (shown here as a shadow
during sunset) is far higher than even the Observatorio del Teide (on the
left of the image). Gill Carter
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Fig. 15.6 A star-trail from the Refuge Altavista, El Teide. Gill Carter
front of me as the Sun set behind it. The shadow gradually coved the
domes of the Observatorio del Teide, a working astronomical observatory
2,854 ft below. I felt privileged; from up here, the view was even better
than for the professional astronomers (Fig.15.6).
Transparent Sky
Refuge Altavista is above the clouds, and a magical place to be in darkness.
During my visit there was a lot of snow on the ground, which is normally a
big hazard for dark skies; even the merest drop of ambient light can be
reflected skywards. However, here there was no light, except for the flashlights of hikers coming down from the peak to find their bed for the night.
By 9pm, everyone else had gone to bed.
By then I was already outside; I noticed the hum of chatter disappear as I
stood in awe at the clarity of the night sky. From my east-facing ledge near
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to the Refuge, Orion was glowing more intensely than I had ever seen
before, with the Pleiades living up to its name, and then some; I could
count ten stars in the Seven Sisters.
Ecliptic onaPlate
I eventually crept into a creaky bunk way after midnight, the freezing conditions having driven me inside despite the stargazing treats above. Just a
few hours later, I was up and dressed as the Refuge emptied out; for everyone here but me the main attraction was a 4 am trek up to the peak of
El Teide to see a sunrise. The first hour required a powerful flashlight.
Climbing through craggy, icy-covered lava is not easy. Just short of the
peak in the scattering light of dawn the entire ecliptic was in full view. In
the east, above the clouds was Venus, shining brightly, and the tiny, dimlylit red dot of Mercury. It was red not because of the planets color, but
because I was looking at it through the Earths atmosphere (much like a
sunset). To the west I could see Mars and Saturn. With these planets visibly
strung-out in a line just before sunrise, the ecliptic really made sense.
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To see the plane of the solar system in full view is a good feeling, but just
as good is the hot air spewing from vents at the top of El Teide, which I
reached just before an orange Sun peaked above the clouds
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Journey totheStars
Fall is the best time of year to visit, says Jrome Brun, Director of
Marketing at Pic du Midi, who meets me in the Haute-Pyrenees village of
La Mongie in the south of France to start my journey to the Nuit Au
Sommet (Nights At The Summit), a package offered by the observatory.
Theres a special pureness to the air at this time of year, but in the winter
season it completely changes because this is a high mountain zone,
headds.
Getting to Pic du Midi is half the fun. If the weather holds and theres no
engineering works, a cable car will whisk you (plus water, food, astronomers and extreme skiers) up from the ski resort town of La Mongie to the
peak in 15 minutes. The panoramas are exquisite as you ascend a kilometer, arriving inside the Observatory beside a gift shop and a restaurant. At
least, thats what they tell me. Unfortunately, on my visit the cable car was
being re-painted in readiness for the upcoming ski season. It was back to
basics. The old mountain road beckoned.
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Telescopes withAltitude
At one end of the facility is the 90ft-tall, cone-like Telescope Bernard Lyot
(TBL), an 80-inch Schmidt-Cassegrain telescope that has been here since
1980. Frances largest telescope, its the main reason why Pic du Midi is still
a working observatory despite the domination of both space telescopes
and the giant computerized telescopes of South America. Its so powerful
that it could read the time on the clock face of Big Ben, 826 miles away in
London, if it wasnt for the curvature of the Earths surface. TBLs two-meter
mirror and 100 ft-long casing have been used to study distant galaxies,
such as Andromeda (Chap. 10), and more recently to reveal the magnetic
fields around stars, including Vega.
As well as an ice cream, Pic du Midi has both an igloo and a Stormtrooper
from Star Wars. The product of French alfresco artists at 65ERS Graffiti,
an igloo is painted on the T60 dome, which houses the observatory s
one-meter Gentili telescope that was first installed by NASA in 1963 to
map the Moon. Its now routinely pointed at the Sun and planets. Firmly
on the dark side in more ways than one, the T1M domewhich is painted
as a Stormtroopers helmethas a 12-inch Meade LX200R telescope that
can be used by amateur astronomers. Standing at the terraces entrance,
the domes give an edgy look to this most isolated of places.
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Nuit Au Sommet
No wonder, then, that the Pid du Midi regularly hosts its Nuit Au Sommet package that begins with five-star cuisine and finishes with a 5,000-star observing
session. As always, such promises must come with the provision clear skies
allowing, and sadly while I was on Pic du Midi the clouds refused to budge.
Acosy night indoors in the modern and simple bedrooms in the Antares Quarter
beckoned for most of the guests, but committed stargazing requires a lax
approach to bedtime. By 5am I was awake, wrapped-up warm and out on the
terrace in the hope of clear September skies. The seeing (Chap. 10) wasnt great,
but such is the clarity at this altitude that I was greeted with a stunning sight; the
winter constellations out in force, and beaming as best they could through the
haze. In the eastern sky the Orion Nebula shone beneath the belt stars while
Siriusand Jupiter dazzled, and the Pleiades poked through the clouds.
Summer was over and I hadnt see these stars for six months; it was like being
back with old friends. Fast-forwarding the sky is the best reason there is for
getting up early (Chap. 3). While I watched, shivering, from Pic du Midi as a
deep orange Venus appear momentarily on the horizon as the Sun rose, I was
reminded of two of the pillars of stargazing. Wherever you are, never take clear
skies for grantedand never give up on finding a gap among the clouds.
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Fig. 15.8 With just 39 cloudy nights each year and a range of powerful telescopes, the Cosmos Centre & Observatory in Charleville, Queensland is an
ideal place to get to know the southern night sky. Credit: Cosmos Centre
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Nights Window
For anyone from the northern hemisphere, standing on the fabulous outdoor observing platform at the Cosmos Observatory is a rare treat, but its
initially disorientating. Im here in March, fall in Australia, and with nights
window open I look across the bush at the southern horizon. I see nothing I
recognize at first glance. Over the next few minutes were shown the famous
Southern Cross, the False Cross above it, and the Pointer Starsone of them
Alpha Centauri, our nearest neighborjust visible in the south. If thats
special treat, its also a relief to be shown familiar Sirius above our heads
and, nearby, two familiar, but odd-looking constellations that on second
glance are an upside-down Orion and Taurus. Below it to the south is bright
Canopus, a common sight in these parts, but completely unknown to me.
Nearby are the Large and Small Magellanic Clouds, two naked eye dwarf
galaxies to rival the Andromeda galaxy. The southern sky is already charming me, and thats without even having looked through a telescope yet.
Into Eternity
Leo and Virgo are climbing in the north-east, and tonight both contain
interlopers, Mars and Saturn. At last its time for a close-up, and the three
motorized telescopes move in sync to point at Saturn close to the horizon.
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Fig. 15.9 Stargazers with a Sun-scope have no need for darkness. Jamie
Carter
We visit a telescope in turn and see its rings, a glorious sight and proof that
for some night sky objects, magnification is everything. However, after a
quick look at Mars, its time to see some of the sparkling sights only visible
from the south (Chap. 13). First into the telescopes goes the fabulous Jewel
Box Cluster in the Southern Cross, an open cluster of over 100 red, white
and blue stars that in a telescope truly lives up to its name. Next up is
Omega Centauri, a 12 billion year-old globular cluster. Looking at its
several hundred stars really does feel like looking into eternity (Fig.15.9).
Sun Viewing
By morning its time for stargazing of a completely different kind. Im back
on the observing platform looking through one of the same telescopes,
but this time its fitted with a solar filter. Blessed with such reliably sunny
weather, Sun viewing sessions like this one are a daily event at the Cosmos
Observatory. I had never looked at the Sun close-up before, and its a
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stunning sight; the disk is exceptionally well defined, and its fizzing with
activity. Today is a particularly good session, with at least ten black areas
visible on the surface, sunspots caused by magnetic field lines becoming
twisted. Im here at solar maximum, the peak of sunspots during the Suns
roughly 11-year cycle. This is when sunspots can lead to more solar flares
and coronal mass ejections that are responsible for sending superheated
X-class flares of plasma particles on a two-day journey towards Earth. The
result is the green aurora that appears in the night sky above the north and
south poles (Chap. 14).
Space Tourism
The aurora is for another trip, and so is my next close-up of the Sun
(Chap. 14). As Im about to fly back to Brisbane, a local journalist stops me
and takes my photo; the resulting story in the Western Times newspaper
with the title International Space Tourist spots the Sun makes me smile,
but its increasingly what myself and many others are doing. With light pollution rampant in the northern hemisphere, traveling across the world
specifically to look away from it is fast becoming essential for anyone after
a clear view of the cosmos. For stargazers, its the night skies from the
Australian Outback that grab all the headlines.
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Fig. 15.10 Sirius and Orion above Lowell Observatorys Clark Telescope
Dome. Its close proximity to Flagstaff has helped the town keep its night
skies dark. Jamie Carter
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The 70,000 residents call their college town Flag, which is rather fitting
since the town is a marker for everything a stargazer needs. Perhaps most
important is altitude. At 7,000 feet (2,130m), theres little moisture up here,
and the seeing is good; there are around 250 clear nights each year.
The altitude and the unbeatable clarity of the skies in Flag is why, in 1894,
Percival Lowell decided to build an observatory on what became known as
Mars Hill. In the years after Lowell Observatorys construction the town
appeared, nominally to serve astronomers and loggers of the surrounding
Ponderosa Pine, vast forests of which stretch from Flag in all directions.
Lighting Ordinance
Flag has darker skies than towns a fraction its size, but not because of geography. Brightly-lit billboards along highways are conspicuous by their
absence, gas station forecourts have canopies to restrict sky-glow, and all the
streetlights have shielded, low pressure sodium bulbs. We were the first
town to adopt laws to try to protect the night sky, says Chris Luginbuhl at
Flagstaff Dark Skies Coalition, a retired astronomer from the near by US Naval
Observatory and something of a stargazing aficionado (Chap. 3). Since then
Flagstaff has become a model for how to keep urban skies dark. Chris and his
colleagues proposed the idea of the town becoming a Dark Sky City back in
2001, a concept that didnt exist at that time. It was then ratified by the
Tucson-based International Dark Sky Association, the same body thats
responsible for certifying the Dark Sky Parks, Reserves and Discovery Sites
now slowly spreading across the planet. We created the idea of a Dark Sky
City, and we did it to help spread awareness throughout the community, says
Chris, who insists that nobody is going to protect things theyre not aware of,
and that dark skies are for everyone to enjoy. To say that the night sky is only
for astronomers is like saying that the Grand Canyon is only for geologists, he
says. Hes right, though Flags historic lighting restrictions do have much to do
with the close position of Lowell Observatory.
Nightly News
Though Percival Lowell himself was obsessed by Mars, its was the discovery of Pluto by Clive Tombaugh in 1930 from Lowells observatory that
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made the headlines. Old habits die hard in Flag. The day I arrived in January
2015 the front page of the local Daily Sun newspaper held a report on an
ugly massacre in Paris, just as all the national newspapers did, but it wasnt
the top story. That privilege went to a report on how stars are more accurately being aged by a group of astronomers, one of them a former
employee at Lowell Observatory. Its probably the only town in America
where astronomy makes the headlines, says Gordon Watkins, the owner of
my lodgings in Flag, the Inn at 410. Its always big news here. The historic
house is just two blocks north of Flags central Heritage Square, but even
this close to the towns bars, hotels and businesses, after dark there are way
more stars than streetlights.
The grip that astronomy has on Flag is obvious, nowhere more so that at
the Inn at 410 itself. Original photography of the Moon, Saturns rings, the
Orion Nebula, Comet Hale-Bop from back in 1997, and several galaxies
adorn the walls of the Observatory Suite. Skywatching by David H Levy and
The Friendly Guide To The Universe by Nancy Hathaway sit by the bed-side
table where you might normally expect to find a Gideons bible. Above the
bed are stunning photographs of an eclipsed Sun.
If the Observatory Suite is unique, its not unexpected in a town with
astronomy woven into its heart. Over at the visitors center, housed in a
1926 railroad station (Amtrak still rumbles through here twice a day on its
way from Chicago to Los Angeles), a dark skies-themed corner section sells
t-shirts adorned with Hubbles deep sky photography, alongside constellation playing cards and stargazing field guides.
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It may be fashioned from rice and seafood in Japanese style, but this
tribute contains some historical accuracy. Legend has it that around 4pm
on February 18, 1930, observing assistant Clive Tombaugh found tiny Pluto
from a distance of 3 billion miles (or 32 AU, Chap. 7) on the photographic
plates hed exposed the night before. He found it after lunch, making it the
only planet to be found in daylight. Tombaugh had just eaten lunch at the
Black Cat Caf in Flag, the present home of Karma Sushi.
Universe inGreen
But Im not in Flag just for lunch. The public stargazing sessions that take
place in front of Lowell Observatorys historic Rotunda each night from
dusk are fast becoming legendary among stargazers.
However, before it gets dark I get a renewed sense of the scale of the cosmos just by walking through the pine forest on Mars Hill. The Galaxy Walk
starts with the Sun and finishes at the galactic center some 500 ft (and
30,000 light years) later. Using a scale of around an inch to five light years,
the solar system is passed after a tenth the width of a human hair. First
comes the solar neighborhood, from Proxima Centauri (Chap. 13) to Sirius,
to Vega to Arcturus 37 light years distant, then the Pleiades and other open
clusters at 440 light years. Then comes star-forming regions like the Orion
Nebula 1,270 light years and the truly colossal star Deneb (Chap. 6), and
ten times further, globular clusters. It ends at an innocent-looking forest
clearing that doubles as a supermassive black hole. The path takes about
10 minutes to walk, which equates to a speed of about one billion times the
speed of light. The nearby Universe Walkwhere the scale is upped to two
million light years per inch just to fit it on the planet, never mind on Mars
Hillis equally staggering.
On a much more manageable scale (a mere one million miles per inch), the
Pluto Walk proves just as eye-opening. It leads from the main buildings to
the aptly-named Pluto Telescope Dome (Fig. 15.11) where Tombaugh discovered the then-ninth planet, but alongside are the relative positions of
the planets; Mercury, Venus, Earth and Mars are all passed by after only a
few steps. Its then quite a march to Jupiter and Saturn before a long gap to
Neptune, Uranus and, finally, to Pluto. The latters dedication is somewhat
poignant. Its interpretation sign stands not 15 yards from where it was
discovered. Its jokingly referred to as Plutos gravestone (Fig.15.11).
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Fig. 15.11 The Pluto telescope with the dwarf planets gravestone beside.
Jamie Carter
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A Comet Close-up
Since its orbit of the Sun is a staggering 248 years, Pluto wont be up in
January until 2065, though its never an easy or impressive telescopic
object. Luckily, there are many more solar system objects to see during my
two evenings up on Mars Hill. An experienced and friendly team of volunteers man the 12-inch and 16-inch Dobsonian telescopes (Fig. 15.12), one
of which is focused on Comet Lovejoy. By lucky chance its near the zenith
and as bright as it will ever get during the week of my visit. If seeing it both
naked eye and close-up was a treat, so was tracking its swift movement
through Taurus to close to the Pleiades over just a couple of nights. There
followed an hour in the McAllister Dome with Jupiter in the way of a
16-inch telescope. As well as identifying seven of its atmospheric bands, I
glimpsed the shadow of one of the Galilean moons (Chap. 11) as it crossed
the giant planets disc. Talk about good timing.
Fig. 15.12 A 16-inch Dobsonian telescope is used each night for public
stargazing at Lowell Observatory. Jamie Carter
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Year ofPluto
The next day I go back to Mars Hill to meet Jeff Hall, the Director of Lowell
Observatory, who during my visit is all-consumed by New Horizons imminent Pluto flyby. I put it to him that Plutos relegation to a dwarf planet by
the International Astronomical Union (IAU) in 2006 must have been hard to
take for Lowell Observatory, and for Flagstaff generally. He shrugs it off.
Personally I like the simplest possible definition of a planet, which is: its a
ball, which means its round as a result of its own gravity, and its not a star,
it doesnt shine, says Hall. That omits not only Pluto, but a whole slew of
things not just in the solar system, but around other stars that were finding. By the current definition of planets, you cant call them planets. It
seems to me to be scientifically a very narrow definition. The IAU has since
decided that dwarf planets are special kinds of Trans-Neptunian Objects
that deserve their own name; Plutoids.
Even if Pluto is considered a Kuiper Belt Object (Chap. 8) rather than a
planet, Lowell Observatory is still committed to the former planet in its
research. The Kuiper Belt is a very interesting region in its own right
were not shying away from the is it a planet? debate, says Jeff, who leads
a team of astronomers who are now studying Kuiper Belt Objects as well as
looking for new exoplanets. In 1930 we discovered a world here at Lowell,
and now we are very heavily into discovering other worlds around other
stars, he says.
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Flagstaff. Winslow looks far brighter. Flagstaff is doing very well indeed,
he says, yet since 2012, Jeff and his colleagues have been using the 4.3meter Discovery Channel Telescope, an enormous structure constructed in
remote forests at Happy Jack, about 40 miles to the south of Flag at a
breathless 8000 ft. Even with the worlds best dark sky ordinance you
would never build a 4.3 meter telescope right next to a city of 70,000 peopleit just wouldnt make sense, he says.
Lighting Zones
Mars Hill wont ever get new telescopes on the scale of the Discovery
Channel Telescope, though astronomy does still thrive around Flag. The
towns lighting zones, which restrict the level of lumens that can be emitted per acre, are keeping a hill just outside the city limits dark enough for
astronomy. Lowell Observatory has four telescopes on Anderson Mesa
while the US Naval Observatory has built an optical interferometer.
Theyre preparing to upgrade that with four more 1.8 m telescopes, at
which point it will be the most sensitive instrument of its type in the world,
bar noneand its just nine miles from a city of 70,000 people, says Hall.
That theyre still willing to do that says a lot about Flagstaffs lighting
ordinance.
383
Precious Legacy
No stargazer could fail to love Flag. Lowell Observatory is a fabulous place
to visit and the Flagstaff Dark Skies Coalitions pioneering work on lighting
ordinance is inspiring. A progressive town where constant pressure on
policy-makers by passionate people is having dramatic results, Flagstaff is
nevertheless not supposed to be a dark sky destination.
Wherever there are humans, there is light, and more of it each year; the
legacy of the Flagstaff Dark Skies Coalition wont be a city with dark skies
above it.
However, its not until I leave Flagstaff for Las Vegas that I see what its legacy will be. Crossing from Arizona into Nevada at Bullhead City90 miles
from Sin Citymost of the sky is inky black and star-studded, but the low
northern sky is already crowned in an orange glow. At Searchlight, 60 miles
out, the north is lost. An hour later from Downtown Las Vegas I could see
only Jupiter, Capella and Rigel.
Light pollution in Las Vegas and countless other urban areas is growing
fast, and most stargazers must now drive many hours to escape the glow.
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True darkness is practically inaccessible. Thats not the case in Flag, where
lighting ordinance means that just a 10 minute drive finds the kind of sky
few people ever get to see. In a world of rampant and unstoppable urbanization, this small town can have a huge legacy.
Spreading theWord
The Brecon Beacons gets its name from the ancient tribal practice of lighting beacon fires on the tops of the areas prominent peaks to communicate, though its the national parks new status thats helping to spread the
word among stargazers. A lot of people have heard of the International
Dark Sky Reserve and they come here specially, says Richard Cooke, who
runs Stargazers Retreat (Fig. 15.13), a converted stables with unfettered
access to a superb custom-built private observatory.
The visual limiting magnitude of two nearby reservoirs, Crai and Usk, has
been measured at +6.4 and +6.37, respectively. Thats about 10,000 stars
visible to the naked eye, which is just about as many as any stargazer can
385
Fig. 15.13 The Brecon Beacons International Dark Sky Reserve is primed
for astro-tourism. Jamie Carter
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Chapter 15
ever hope to see. Crai and Usk are both are Dark Sky Discovery Sites, but
Stargazers Retreat is between the two, and on higher ground with clear
views to the horizon in the east and south. A lot of stargazers come here
and cant believe how much more they can see in a dark sky environment
just with the naked eyeyou can see magnitudes more, says Richard.
When you have stars 360 degrees around you, it really brings the sky to
life. Its like exploring a new world.
Cold Comforts
For those after the very darkest, clearest skies, winter is the best time to visit
the Brecon Beacons, which does mean freezing temperatures. I always tell
guests to bring extra warm clothes because theyre going to want to be
outside for at least a couple of hours, says Richard. Even during my visit in
May the nights were very cold, and occasionally cloudy, but the observatory
is well prepared. As well as soft red down-lighting below waist height, its
got built-in heaters. Theyre useful for the initial set-up, though theyve got
to be switched-off when using the telescope because the heat interferes
with the optics. Heat causes very small fluctuations around the telescope
that you cant see until you look through the eyepieceeven planets are
wobbly, he says, adding that the heaters are of most use during the winter
when clouds sweep over and everyone has to wait. You can stargaze a lot
longer without freezing, though flasks of hot drink also work well.
387
A Stargazing Schedule
Back at Stargazers Retreat firmly in the western zone, Richard offers a few
tips on savvy stargazing. As well as giving your eyes enough time to get
dark-adapted, he advises knowing how to operate a planisphere and, if
you want to make the most of your time, knowing exactly what you want
to see. Have a list before you go out, then youve got goals to work
towards. Otherwise youre just looking at dots in the sky and getting cold,
he says. If you know what you want to find and tick them off as you go,
your enthusiasm for doing it again will be so much higher.
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For my own visit I had an observing list, prepared back at home in the city,
for my visit, but the skies were so dark that it quickly went out of the window. That was partly down to the appearance of Saturn, rising above
Antares. The latter in binoculars was the brightest orange I had ever seen
it. Its accomplices in the head of Scorpius were especially bright too,
though at these mid-northern latitudes the stinger below never rises.
Point andShoot
The observatory at Stargazers Retreat isnt just warm and red, its also
motorized. Hooked-up to free planetarium software Stellarium, the Meade
ETX-125EC telescope is a point and shoot affair. While its slewing to Saturn,
I notice that two constellations that often get rubbed-out by urban skies,
Corona Borealis (Chap. 6) and Coma Berenices (Chap. 5), are obvious above.
The seven stars of Corona Borealis are unmistakable, particularly the jewel
in the so-called Northern Crown, Alphecca.
More of a treat was Coma Berenices, the scant three-pronged constellation
strung between Bootes and Leo that tends to disappear with even a whiff
of light pollution. Inside it the Coma Cluster was an easy naked eye target,
as were the two brightest stars of the tiny Baby Giraffe asterism (Chap. 6)
near Cor Caroli. Above me the Big Dipper, wrapped in an obvious Ursa
Major, dominated as a vast anchor.
Telescope Tutorials
I used the telescope to hunt-down a few globular clusters, though many visitors to Stargazers Retreat bring their own telescopes. A lot of people who
bring their own telescopes dont know how to use them, says Richard, who
offers to show them how to set them up and align them in the dark. Thats
not a skill to underestimate, and certainly not one that comes naturally to
most casual stargazers. With a box full of accessories, spares, various camera
adaptors and webcams in the observatory, were soon taking pictures of
Saturn, and even filming a short video of the planet in motion. Tracking
objects in the night sky is a fabulous skill of motorized telescopes, but sometimes its more dramatic to watch a planet speeding across the field of view.
389
All-Weather Stargazing
The Brecon Beacons demands a much slower look. Its best to hang around
for at least three nights because while most places get clear skies or bad
weather, Wales often gets both at once. Its one of the few places where its
possible to stargaze while getting wet, and one of the reasons why
Stargazers Retreat has plans for all-weather sky-watching. Construction of
a small planetarium is taking place in the woodland during my visit; the
aim is to eventually have both a live projection of the sky and completely
remote viewing via the telescope. That will be great on a wet day, but
when the clouds part above this International Dark Sky Reserve youll
want to be outside to witness what the Brecon Beacons has to offer; an
awesome view of the Universe from one of its most beautiful corners.
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Southern Sky
Most tourists tread the Inca Trails 27 miles of arduous steps for both a
sense of achievement and for the prize of seeing Machu Picchu in the light
of dawn. Treks are organized out of the city of Cusco, already 11,150 ft
above sea level. Its best journeyed to slowly to lessen the chance of altitude sickness.
The trails itself is all about mountain vistas and the Inca culture along the way,
but theres plenty of the latter to see after dark, too. In these equatorial skies
there are plenty of stars both familiar and strange to northern hemisphere
stargazers; its the perfect latitude to add to your knowledge of the southern
hemispheres quixotic night sky (Chap. 13) without getting too confused.
391
Dark Constellations
As well as learning about new stars, and seeing old stars from a new perspective, Peru is a great place to see the Milky Way in all of its glory. Down here
the extra half-a-sky of Milky Way is more brilliant, brighter and bigger than
the sections visible from the northern hemisphere. However, the distinction
between studying the stars and admiring the Milky Way was one I brought
with me; Western stargazers tend to treat the Milky Way and constellations
as two different sights. Not so in Peru, where the shapes within the Milky Way
are actually the night skys key constellations, as I learned at Planetarium
Cusco, a small observatory on a hillside above the former Inca city.
The Black Llama, the Baby Lama, the Snake, the Fox, and the Frog. These are
the dark constellations made not from joining-up stars, but from describing
the shape of darkness between the stars within the Milky Way, which the
Inca called mayu, or river. Used by the Inca and still familiar to the local
Quechua people of Peru today, its perhaps the Black Llama thats the most
impressive Inca constellation; not only is this dark shape easy to see on a
clear night, but its eyes consist of Alpha and Beta Centauri, the nearest two
stars to our own solar system. Look into the eyes of the llama and youre
looking at our neighbors. Planetarium Cusco is a great place to get acquainted
with the Inca constellations ahead of an attempt at the Inca Trail (or any
other multi-day hike in the vast Sacred Valley area), but it also lets you gets
eyes-on through a telescope with some special southern hemisphere sights
such as the Jewel Box Cluster and the endless clusters and nebula around the
Southern Cross. Waterproof binoculars in a backpack are a must.
Moonless Mayu
The Milky Way is usually something that can only be glimpsed. Beautiful
astro-photography is now familiar to everyone thanks to the internet and
social media, with the Milky Way so often depicted as arching from one
horizon to another in purples, oranges, greens and reds. Consequently,
when most people finally see it theyre disappointed. Its neither as bright
nor as colorful as they had expected. Most people dont notice it even
when theyre in a dark sky zone.
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From the Inca Trail, mayu is impossible to ignore. If walking during a New
Moon (the golden rule of any pre-planned high altitude hike) and under
clear skies, its right there, hanging over your campsite and stretching
down behind the mountain peaks. If youre camping, its one of the few
times that your eyes adapt to the dark as it gathers; stargazing can commence during twilight and, this near the equator, that means about 6pm.
393
Fig. 15.15 The Southern Cross carving at Machu Picchu, Peru. Jamie
Carter
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Chapter 15
No one knows for sure what the unique celestial design of Machu Picchu
means, only that it has one. Look at the clarity of the stars from the
Urubamba Valley, its perhaps not surprising, but this is a night sky you
have to work for. While the day-trippers to Machu Picchu must stay in
Aguas Calientes in a valley far below the lost city, only hikers enduring the
Inca Trails seemingly endless high-altitude path get the full, breathtaking
experience of a staircase to the stars.
Fig. 15.16 Hawaii has 325 clear nights a year, and the northern hemispheres biggest telescopes including Keck, Subaru and Gemini. Credit:
Hawaii Tourism Authority (HTA)/Dana Edmunds & www.gohawaii.com
395
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397
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Chapter 15
Southwest USA
Location: Arizona, California, Nevada, New Mexico and Utah
Latitude: 3631 degrees North
Altitude: Various
Best time to visit: Year-round
The eastern half of the USA is awash with light pollution. There are some
dark spots (such as Cherry Springs State Park in Pennsylvania), but most
are in the southwest. In fact, there are more than ten International Dark Sky
Parks in Arizona, California, Nevada, New Mexico and Utah, where clear
skies and low humidity give year-round stargazing potential.
The darkest is reckoned to be Natural Bridges National Monument in
southeast Utah, the first (and some say best) International Dark Sky Park,
Park, though Arches National Park nearby is just as dark. In the south-west
of the state is the ever-popular Bryce Canyon National Park (which holds
stargazing lectures and guided observing every week in summer), and the
lesser-known but super-dark Cedar Breaks National Monument near Brian
Head and Cedar City. That the National Park Service in the USA is now fighting to protect, preserve and improve the darkness of its skies is a huge help
for stargazers in North America. There are also several observatories to
choose from that host public observing sessions, including Lowell
Observatory in Flagstaff, Arizona, Kitt Peak National Observatory southwest of Tucson, Arizona, and McDonald Observatory near Fort Davis, Texas.
399
A gold-rated International Dark Sky Reserve and the largest in the southern
hemisphere, the 2670 square miles of Aoraki Mackenzie in the South Island
of New Zealand includes Mt John Observatory at Lake Tekapo, NewZealands
foremost observatory. Several day and night tours of the observatory are
available as well as guided stargazing tours. Like Flagstaff, the Aoraki
Mackenzies transparent skies are down to lighting ordinance, which has
been in place since 1981.
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Chapter 15
Fig. 15.18 The far side of the Moon would be the ultimate dark sky
destination. Credit: NASA/Goddard/Arizona State University
401
As viewed from the Moon, the stars would be about a third brighter than
they appear to be when observed from Earth.
For stargazers and astronomers, the other side of the Moon (which no
human has yet set foot on) could become a favorite vacation spot of the
future, with 24-hour stargazing possible during the Full Moon. Why not?
Australia
Cosmos Centre and Observatory, Charleville, Queensland
enquiries@cosmoscentre.com
www.cosmoscentre.com
Chile
Chile Tourism
chile.travel/en
European Southern Observatory
Weekend tours to Paranal, La Silla and ALMA observatories
www.eso.org
Turismo Astronomie (observatory tours)
www.astronomictourism.com
Finnish Lapland
Adventure By Design (aurora photography expeditions)
adventurebydesign.fi
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Chapter 15
Aurora Zone
www.theaurorazone.com
France
Observatoire du Pic du Midi and Pic du Midi International Dark Sky
Reserve, Hautes-Pyrnes
www.picdumidi.com
Hungary
Zselic National Landscape Protection Area and International Dark Sky Park
zselic.csillagpark.hu
Hawaii
Hawaii Tourism Authority
www.gohawaii.com
Mauna Kea Observatories
www.ifa.hawaii.edu/mko
Haleakala National Park
www.nps.gov/hale
Mauna Kea Summit Adventures
www.maunakea.com
Morocco
SaharaSky Observatory and Kasbah Hotel
www.saharasky.com
www.hotel-sahara.com/hotel
New Zealand
Aoraki Mackenzie International Dark Sky Reserve
www.mtcooknz.com/mackenzie/stargazing
403
Namibia
NamibRand International Dark Sky Reserve
www.namibrand.com
Peru
Planetarium Cusco
www.planetariumcusco.com
Machu Picchu World Heritage site
www.machupicchu.gob.pe
Scotland, UK
Galloway Forest International Dark Sky Park
scotland.forestry.gov.uk/forest-parks/galloway-forest-park
Scottish Dark Sky Observatory
www.scottishdarkskyobservatory.co.uk
Switzerland
Alpine Astrovillage L-Stailas Observatory and Center for Astrophotography
www.alpineastrovillage.net
Tenerife, Spain
Parque Nacional del Teide
www.telefericoteide.com
Parador de Canadas del Teide Hotel
www.parador.es
USA
Big Bend National Park and International Dark Sky Park, Texas
www.nps.gov/bibe
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405
Wales, UK
Brecon Beacons National Park and International Dark Sky Reserve
www.breconbeacons.org/stargazing
Llangoed Hall
www.llangoedhall.co.uk
Stargazers Retreat
www.breconcottages.com/cottages/brecon/stargazers-retreat
Reference
Childrey, Don. Star Trails Navajo: A Different Way to Look at the Night Sky. Trafford Publishing, Canada, 2004.
Appendix
407
APPENDIX
Stargazing Resources
Stargazing Websites
BBC Sky At Night magazine: www.skyatnightmagazine.com
Cosmic Pursuits: http://cosmicpursuits.com
EarthSky: www.earthsky.com
Heavens Above: www.heavens-above.com
Jodrell Bank Centre for Astrophysics, The Night Sky: www.jb.man.ac.uk/
astronomy/nightsky
Moon Connection: www.moonconnection.com
Sky & Telescope magazine: www.skyandtelescope.com
Solarham: www.solarham.net
Space Weather: www.spaceweather.com
Stargazers Lounge: www.stargazerslounge.com
Universe Today: www.universetoday.com
408
Appendix
Eclipse Websites
Eclipser (climatology and maps for eclipse chasers): eclipser.ca/
NASA Eclipses (dates and durations): eclipse.gsfc.nasa.gov/eclipse.html
Mr Eclipse (eclipse photography): www.mreclipse.com/
Stargazing Podcasts
Astronomy Cast with Fraser Cain & Dr Pamela Gay
www.astronomycast.com
Jodcast: The Night Sky This Month with Ian Morison
http://www.jb.man.ac.uk/jodcast
Sky & Telescope: Sky Tour PodcastsDiscover the Night Sky
www.skyandtelescope.com/observing/astronomy-podcasts
Appendix
409
Further Reading
Beston, Henry. The Outermost House: A Year of Life on the Great Beach of Cape
Cod. St. Martins Griffin, NewYork. 1988.
Bogard, Paul. The End Of Night: Searching for Natural Darkness in an Age of
Artificial Light. Fourth Estate, London. 2013.
Chiravalle, John A.Pattern Asterisms: A New Way to Chart the Stars. SpringerVerlag London (2006)
Consolmagno, Guy & Davis, Dan M.Turn Left at Orion: 4th Edition. Cambridge
University Press, Cambridge. 2012.
Morrison, Ian. Introduction to Astronomy & Cosmology. Wiley-Blackwell,
London. 2008.
North, Chris & Abel, Paul. The Sky At Night: How To Read The Solar System. BBC
Books, Random House, London. (2013)
Sagan, Carl. Cosmos: unabridged edition. Random House Publishing Group,
USA. 2011.
Scale, Robin. The Urban Astronomy Guide: Stargazing From Towns & Suburbs.
Philips, London. (2014)
Seronik, G.Binocular Highlights: 99 Celestial Sights for Binocular Users Sky &
Telescope Stargazing. Sky Publishing, USA. 2007.
Sparrow, Giles. The Universe And How To See It: A Practical Guide To Viewing &
Understanding The Night Sky. Marshall Publishing, London. (2001)
Index
A
Albireo, 179, 194, 226228, 248
Alcor, 19, 96, 127, 179, 247, 297
Alcyone, 255, 257
Algol, 129, 259261
Almach, 212, 238, 248, 260
Alpha Centauri, 60, 129, 152, 293,
308, 310312, 372
Alpha Persei, 261, 262
Altair, 140, 152, 181, 193, 194, 227,
307, 308
Andromeda, 50, 51, 108, 209, 211,
212, 229, 231, 234238, 242,
244, 246, 248, 260, 267, 273,
298, 317, 324, 357, 368, 372
Antares, 46, 47, 161163, 166, 169,
172, 196, 197, 369, 388
Apollo, 291, 299, 300, 366
Apollo 11, 299, 300
Apollo 17, 299, 300
Apps, 8, 14, 5154, 78, 134, 371
Aquarius, 117, 147, 161, 238242
Arctic Circle, 347
Arcturus, 6062, 69, 9092, 119,
123, 219, 379
Argentina, 306, 338
Astrology, 146148, 150152
B
Bailys Beads, 330, 331
Barlow, 255, 271274
Barnards Star, 20, 128, 129,
152153
Beehive, 105107, 109, 126, 171,
281, 288, 324, 358, 365
Beehive Cluster, 105107, 109,
126, 288, 324, 358, 365
Bellatrix and Collinder 69, 284
411
412
Index
C
Canary Islands, 65, 354, 361
Cancer, 105, 106, 118, 139, 146,
147, 365
Canes Venatici, 91, 142144,
247248
Canon, 287
Canopus, 60, 295, 315317, 319,
324, 372
Capella, 39, 47, 63, 70, 139, 196,
209, 219, 246, 255, 258, 262,
294, 298, 383
Capricorn, 139, 146, 147, 151, 152,
209, 225, 295, 323
Carina, 46, 68, 262, 311, 322
Cassiopeia, 2224, 70, 94, 100,
114, 157, 191, 197, 205, 215,
234, 260, 263, 264, 267,
291293, 298, 306, 311, 358,
360
Castor, 39, 47, 65, 126, 128, 139,
148, 255, 289, 290, 294
D
Dark skies, 103, 111, 126, 154,
267, 284, 301, 305, 320,
351353, 361, 362, 376, 377,
383, 386, 387, 399
Index
Deep sky, 103, 108, 109, 209, 218,
238, 377
Delphinus, 181, 239, 249, 250
Deneb, 46, 70, 140, 179181, 193,
200, 227, 264266, 295, 307,
308, 379
Diamond ring, 330, 332
Discovery, 229, 376, 377
Dobsonian, 216, 225, 380, 381
Double stars, 72, 117, 129, 130,
215, 231, 238, 246248, 257,
261, 288, 299
Draco, 111113, 150, 233, 265, 306
Draconids, 233
Dumbbell, 227229
E
Eclipse, 13, 36, 52, 76, 77, 80, 189,
325344, 349
Ecliptic, 57, 58, 71, 79, 104, 106,
139, 147, 150, 151, 161, 164,
166, 171, 174, 175, 192, 197,
199, 241, 268, 295, 308, 323,
325, 365
Electra, 255, 257
Epsilon Lyrae, 129, 130, 179, 247
Equatorial, 14, 155, 219, 220, 268,
307, 362, 390
Equinox, 57, 71, 146, 161, 173,
209, 240
Eta Carinae, 46, 312, 322323
Europa, 104, 268, 269
Exoplanets, 181, 200, 201, 271, 381
Eyepiece, 96, 214, 220, 223, 227,
236, 241, 247, 249, 252, 260,
268, 272274, 277, 290, 292,
336, 386
F
Fiji, 306
Flagstaff, Arizona, 374, 398
Flashlight, 8, 10, 12, 158, 349, 355,
365
Focal, 214, 220, 272
413
G
Galactic Center, 151, 161, 168
Galilean, 104, 252, 255, 267271,
380
Gamma Delphini, 249
Ganymede and Callisto, 268
Garnet, 197, 264, 266267
Gemini, 39, 60, 63, 65, 66, 105,
106, 128, 139, 147149, 151,
174, 263, 288290, 294, 394
Geminids, 93, 294, 295
Globular, 103, 109, 117, 119, 120,
163, 171, 172, 194, 195, 212,
215, 250, 318, 320, 353, 373,
379, 388
Globular cluster, 103, 109, 117,
119, 120, 163, 171, 172, 194,
195, 212, 215, 250, 318, 320,
353, 373, 379, 388
Go-To, 219, 221
Grand Canyon, 114, 356362,
376, 404
Great Square, 27, 210212,
234, 237240, 250,
298
Green, 163, 227, 229, 242,
344, 345, 348, 349,
374
Grimaldi, 276
H
Hadar, 311
Hemisphere, 3, 7, 14, 16, 19, 24,
26, 39, 49, 62, 65, 76, 80, 85,
91, 109, 120, 146, 147, 161,
169, 171, 176, 194, 197, 204,
209, 231, 241, 255, 262, 268,
276, 294, 295, 298, 305310,
313, 315, 317, 323, 325, 345,
362, 372, 374, 390, 391, 394
414
Index
I
Image stabilization, 287
Inca, 193, 323, 390394
Instagram, 251254
International Dark Sky
Association, 376
International Space Station (ISS),
53, 117, 131136, 203
Io, 104, 268
Iridium, 231233
J
Jewel Box cluster, 312, 314
Jupiter, 14, 26, 44, 59, 75, 104, 131,
150, 154, 158, 163, 164, 166,
174, 234, 250, 252253, 255,
267271, 273, 291, 297, 324,
354, 369, 379, 380, 383
K
Kepler, 130, 200, 203, 250, 276
L
Large Magellanic Cloud, 242,
317319
Latitude, 36, 65, 100, 161, 169,
220, 322, 354, 362, 390, 397
Leo, 71, 72, 74, 75, 91, 105, 106,
121, 123, 143, 147, 148, 150,
161, 243, 255, 295, 372, 388
Lepus, 282
Light pollution, 11, 12, 77, 80, 98,
106, 110, 127, 192, 261, 285,
347, 351, 353, 354, 357359,
362, 374, 382384, 387, 388,
395, 396, 398
Light year, 17, 19, 20, 26, 27, 29,
39, 4244, 4651, 60, 63, 75,
91, 97, 98, 103, 105108,
120, 121, 123, 125, 128130,
140, 142, 143, 152, 163, 169,
171, 172, 181, 194, 195, 198,
202, 227, 234, 238, 240244,
247249, 251, 260263, 266,
267, 282284, 288290, 293,
297, 308, 311, 313, 315, 317,
318, 320323, 353, 357, 379
Limiting magnitude, 218
Local Group, 123, 237, 238,
242244, 261
Lunar, 5, 33, 76, 80, 147, 154, 166,
182, 274, 276, 307, 325, 326,
339344
Lunar calendar, 154
Lyra, 93, 120, 125, 129130, 140,
179, 200202, 250, 262
M
M15, 249250
M27, 227229
M31, 234237
M33, 235, 237, 238, 353
M35, 65, 288290
M36, 63, 262, 263
M37, 63, 262, 263
M38, 63, 262, 263
M41, 100103
M42, 49, 9899, 109, 215, 280282
M45, 4243, 109
M46, 103
M47, 103
M50, 103
M71, 120, 194, 195
M81, 243246
M82, 244246
Index
Magnetic field, 269, 368, 374
Magnification, 89, 95, 96, 103,
212215, 217, 220, 221, 227,
236, 238, 243, 246, 257, 262,
271274, 279, 280, 285, 287,
292, 320, 336, 373
Magnitude, 117, 125127, 129,
152, 172, 176, 181, 217, 218,
229, 242, 245, 246, 249, 250,
261, 266, 267, 285, 293, 353,
354, 384
Mars, 59, 161, 163, 166, 167, 198,
255, 269, 271, 291, 297, 299,
365, 372, 373, 376, 378,
380382
Meissa, 197, 284
Melotte 20, 259, 261, 262
Mercury, 44, 59, 75, 76, 80,
165167, 173, 174, 176178,
198, 255, 269, 271, 273274,
290, 295, 358, 365, 378
Merope, 255, 257
Messier, 109, 110, 171, 199, 240
Meteor shower, 34, 76, 84, 93,
117, 185, 190, 233, 240, 255,
260, 279, 294, 295, 362,
Milky Way, 14, 20, 24, 3940, 43,
4951, 62, 63, 72, 91, 106,
107, 113, 119, 121, 123, 124,
128, 143, 156, 159, 161,
166169, 171, 172, 179, 181,
193, 197, 200, 201, 212, 234,
236, 237, 242, 244, 245, 249,
258, 260, 263, 270, 289, 291,
294, 298, 306, 308310,
312315, 317, 318, 320, 323,
343, 353, 354, 358, 359, 381,
391, 392
Mirfak, 258, 260, 261
Mizar, 17, 19, 96, 127, 179, 247, 297
Moon, 174, 252, 269, 271, 299, 330
Moon-rise, 155, 276
Moon-shadow, 331, 334, 338
Motorized, 219, 225, 273, 372, 388
415
N
National park, 343, 357, 358, 366,
382, 384, 387
Navajo, 114, 360, 361
Nebula, 49, 129, 161, 169171,
193, 196, 215, 228, 229, 246,
299, 308, 315, 322, 391
Neptune, 53, 59, 199, 229, 239,
241, 242, 324, 379
New Zealand, 306, 313, 338, 344,
346, 398399
New General Catalogue (NGC),
75, 110, 193, 235, 238, 245,
246, 260262, 283, 284, 288,
289, 292, 314315, 318322,
353
NGC 752, 235, 238
NGC 869, 260261
NGC 884, 260261
NGC 2169, 288, 289
NGC 2264, 283, 285
NGC 2403, 245, 246
NGC 2516, 262
NGC 4755, 314315
NGC 5128, 321
NGC 5139, 320321
NGC 7000, 193, 353
North American Nebula, 193,
353
Northern lights, 204, 295, 296,
325, 346347, 397
O
Objective, 95, 213, 217
Observatory, 214, 215, 285, 307,
364, 366, 368, 372, 376, 384,
386, 388, 391, 395, 396, 399,
401
Ocean of Storms, 275, 276
Omega Centauri, 119, 171,
320322, 373
Ophiuchus, 44, 128, 151154, 162,
169, 225, 295, 323
416
Index
P
Park, 4, 293, 358, 361, 366, 374,
387, 396, 403
Partial, 327330, 332, 333, 335,
340, 341, 344
Pavo, 154, 319, 324
Pegasus, 27, 197, 209212, 234,
237239, 249250, 298
Perseids, 93, 185, 190, 191, 193,
260, 361
Perseus, 63, 94, 100, 101, 103, 168,
191, 209, 212, 237, 258266,
314, 358
Peru, 193, 323, 351, 390394, 403
Phases, 7883, 93, 189, 223,
273274, 289290, 308, 330
Photography, 7, 155, 157, 185, 203,
335, 348, 349, 366, 377, 391,
396, 402
Pic Du Midi, 366370
R
Red, 10, 12, 14, 37, 44, 5355, 60,
75, 78, 104, 123, 129, 132,
154, 161, 163, 166, 195197,
202, 216, 221, 222, 229, 265,
267, 268, 284, 292, 310, 314,
331, 340, 349, 355, 365, 372,
373, 386, 388
Reflector, 215
Refractor, 215217, 223, 249
Reserve, 369, 399
Rigil Kent, 311
Royal, 161162, 164, 239, 240, 371
Index
S
Sagitta, 120, 194, 195, 229
Sagittarius, 19, 120, 147, 151, 152,
161, 168172, 179, 193, 197,
198, 225, 263, 285, 308310,
323, 324, 353, 354, 362
Sagittarius Arm, 168, 179, 193,
263, 308310
Satellites, 55, 131, 137, 189, 222,
223, 232, 275, 339, 386
Saturn, 59, 154, 163, 166, 212, 215,
225226, 234, 266, 267, 271,
291, 297, 323, 324, 365, 371,
372, 377, 379, 388
Scorpius, 46, 47, 114, 161, 163,
166, 168, 169, 171, 172, 225,
323, 361, 362, 388
Shadow, 80, 133, 191, 223, 270,
276, 318, 325, 326, 328, 330,
331, 334, 338341, 343, 353,
363, 380
Shadow bands, 330
Shooting stars, 93, 117, 178, 191,
255, 279, 294
Sirius, 2427, 31, 37, 39, 44, 45, 47,
49, 51, 60, 63, 65, 70, 90,
100103, 107, 126, 139, 176,
196, 219, 233, 282, 294, 295,
297, 298, 307, 315, 317, 369,
372, 375, 379
Small Magellanic Cloud, 242,
317, 318, 372
Smartphone, 10, 11, 14, 5154, 78,
100, 105, 158, 231, 251254,
296, 335337, 343, 348, 371
Solar, 13, 24, 36, 37, 43, 44, 46, 4952,
5759, 72, 76, 77, 79, 105, 118,
123, 124, 128, 132, 154, 163,
166, 171, 173, 174, 179, 185,
189, 190, 192, 195, 197200,
213, 241, 250, 261, 263,
266268, 270, 271, 284, 298,
311, 324339, 343, 345, 349,
366, 373, 379, 380, 391, 395
417
418
Index
T
Taurus, 39, 4144, 60, 63, 105, 139,
147149, 161, 242, 255, 258,
262, 285, 294, 299, 307, 323,
372, 380
Taurus-Littrow, 299
Teapot, 169172, 198, 310, 354
Teide, 361366, 403
V
V762 Cass, 264
Vega, 63, 70, 113, 125, 126,
128130, 140, 152, 193, 200,
227, 240, 247, 265, 295, 298,
307, 368, 379
Venus, 59, 75, 76, 80, 98, 131, 158,
164167, 173, 175178, 198,
U
Uranus, 59, 164, 229, 239, 241,
242, 324, 379
Ursa Major, 17, 7173, 107, 111,
129, 142, 243, 360, 388
Index
419
W
Wales, UK, 384389, 405
Z
Zeta Aquarii, 241
Zodiac, 147148