Talk:Ephemeris

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The changes on Feb 5, 2005, attributed to 69.244.72.110 were due to Pdn, who thought he was logged in, but that was in a different window. sorry

The Wikisource ephemerides are empty - does anybody know where the data is? Autarch

Not sure if this is the right place but, the Rig Veda definitely postdates the Middle Bronze Age; the bullet under "History" that:

2nd Millennium BC — Panchanga tables based on Jyotisha in the Vedic period of Indian astronomy.[citation needed]

isn't strictly false in the sense that the Rig Veda was likely composed in the second millennium but, what is considered "Jyotisha" or Hindu astrology, wasn't elaborated till much later. For example, the Rig Veda mentions demons causing eclipses and some of the later material (Atharvaveda and Chandogya Upanishad) also mention eclipse-demons, especially Rahu. The most firmly datable Indian astrological/astronomical texts are either translations from Greek (Yavanajataka) or much later medieval compositions (Brihat Parashara Horashastra). (sources are from the wiki article on Hindu astrology which is well sourced. In essence this bullet point is like attributing astronomy to the ancient Hebrews because of Joshua 10:13, when the sun stood still for Joshua at Gibeon and Ajalon. So if it's okay, and because the citation needed has been there for almost 4 years, I will go ahead and delete this bullet point. This is the citation left there: ^{[citation needed]} 2601:480:4101:B790:8C8D:90FF:C2DC:65AC (talk) 01:43, 29 January 2016 (UTC)[reply]

The articles does currently not differentiate between astronomical tables, like Tabulae Rudolphinae, and an actually computed ephemeris.

An Ephemeris is an actual list of daily (or other regular interval) positions of a celestial body. Astronomical tables are something different, they contain tabular data out of which positions of a celestial body can be computed, by a more or less simple procedure orf multiple steps (looking up numbers, adding, mulitplying, interpolating) but they do not yet contain the actual positions.--213.3.22.4 (talk) 04:57, 5 June 2009 (UTC)[reply]

I would like verification of the claim, "The majority of astrologers study tropical astrology" Warrensson (talk) 13:36, 27 June 2009 (UTC)[reply]

I would really like to see these separated into two articles. Opinions? Pro: much easier to elaborate on both subjects. Astronomers mostly think of astrology as a pseudo-science, Astrologers have little use for astronomer's ephemerides, as they calculate a completely different way. Con: ephemeris is the same word, with essentially the same meaning, for each of the two Tfr000 (talk) 22:29, 2 January 2012 (UTC)[reply]

This would also allow to stop using the words "scientific" and "astrological" every time the word "ephemeris" appears. No one in the astronomical community uses a term like "scientific ephemeris". Tfr000 (talk) 22:51, 2 January 2012 (UTC)[reply]

MocuAed (talk) 05:31, 29 June 2012 (UTC) says: Re: separating Astronomy from Astrology: I agree with your approach because I am of the same opinion. At the same time I am under the impression that this particular article was intended as a "comparison" or as a "parallel" of astronomic and astrologic ephemerides, so maybe there is a place for it as such? If the historical perspective be enhanced and the content organized, it might become of some value. This is just a suggestion. Which, if applied, would rise the question: since it is a parallel look at ephemerides in astronomy and astrology, would it be reasonable to coin them "astronomic ephemerides" and "astrologic ephemerides" for this purpose? MocuAed (talk) 05:31, 29 June 2012 (UTC)[reply]

Agree. I'll just move the astrology stuff to ephemeris (astrology) and keep the unqualified name for ephemeris in its scientific sense, as in a encyclopedia, science has priority over obscurantism . Bomazi (talk) 17:55, 17 January 2013 (UTC)[reply]

I see someone deleted the astrology content. Hopefully, they moved it someplace appropriate before doing so. There's nothing wrong about non-scientific content, it simply isn't a good idea to blend the two together in one article - confusing. An encyclopedia, being encylopedic, should cover both. Tfr000 (talk) 14:09, 21 April 2013 (UTC)[reply]

Someone simply deleted the astrology stuff (diff) and it looks as if it was never put anywhere else. I think this improved the present article but it seems a pity the information was not put in Ephemeris (astrology) (if indeed there is such a thing). I know nothing about astrology and so can't sort it out. Thincat (talk) 12:21, 7 November 2013 (UTC)[reply]

I'd be inclined to keep both kinds of ephemeris in the same article. The calculation of the positions of interest only to astrologers is, as far as I know, carried out in a neutral manner, in much the same way as it would be computed by astronomers. The pseudoscience comes in how the astrological ephemerides are used. Some of the data which the removed material claims is not present in astronomical ephemerides is only absent from paper astronomical ephemerides. In electronic ephemerides such as the Multiyear Computer Interactive Almanac some of the so-called astrological data is present, such as geocentric ecliptic latitude and longitude of planets.

People interested in astronomy who don't understand how to use some of the sophisticated electronic ephemerides and don't have the skills to transform positions in printed ephemerides to the coordinate system they are interested in might like to know about astrological ephemerides, since they might happen to have the data they are interested in without having to do any tricky transformations.

I know very little about astrology, but maybe astrologers would want to be exposed to the data available in astronomical ephemerides too; maybe they would have some use for the data that isn't usually provided in astrological ephemerides. Jc3s5h (talk) 14:55, 7 November 2013 (UTC)[reply]

I'd have thought if an astrologer wanted to know where some celestial body actually was in the sky by using an astronomical ephemeris, they could do so and read up a bit about it here and not be bogged down with all sorts of baggage. But I thought (and I expect I'm wrong) astrologers didn't give a toss about what was where in the sky. When they say the sun is in Aries its really in the constellation of Pisces (generally). Astrological sign hints at this: "Precession results in Western astrology's zodiacal divisions not corresponding in the current era to the constellations that carry similar names". Thincat (talk) 17:31, 7 November 2013 (UTC)[reply]

The popular western astrologers (who would be writing the horoscopes published in American newspapers, for instance) do keep track of the actual locations of the planets. They use the same ecliptic coordinate system that astronomers do, they just use different nomenclature for the coordinates. So an ecliptic longitude between 0 and 30° would be called Aries, between 30 and 60° would be called Taurus, etc. I believe astronomers used to use this nomenclature a few hundred years ago. An abbreviated version of this nomenclature can be found in Nautical Almanac and Astronomical Ephemeris for the year 1767; numbers are used instead of names for the signs, but otherwise the nomenclature is the same as used by astrologers. Jc3s5h (talk) 17:58, 7 November 2013 (UTC)[reply]

When I moved to a new job in Aberdeen, people would talk about the "blue buses". Since I had never seen a blue bus I plucked up courage to ask what they were. This caused great amusement because the blue buses were painted yellow and green. The livery had been changed years and years earlier but everyone still referred to them as "blue". Thincat (talk) 10:15, 9 November 2013 (UTC)[reply]

Since my change was reverted, there seems to be a need for discussion.

Firstly, about the factual content. Since the original Greek ἐφημερίς/ἐφήμερος has a (long) η in that position (a short e would be ε), it would be very surprising if the Latin had a short e (denoted ĕ) in this place. Vowel lenght was felt much more important in ancient Latin and Greek than in modern English, so this would not normally have changed easily.

Secondly, the citations. I don't have access to the source given (American Heritage Dictionary of the English Language), but I have a different paper source supporting what I wrote (Langenscheidts Handwörterbuch Lateinisch–Deutsch). Also the English Wiktionary entry gives a macron in this position, and while it isn't itself a valid source and also doesn't give one, it's French sister entry (which also gives a long IPA pronunciation) does give an online source.

Perhaps the American Heritage Dictionary of the English Language was referring to English pronunciation or simply made a mistake. --SpecMade (talk) 21:08, 22 October 2013 (UTC)[reply]

I suggest we just remove the disputed Latin; it doesn't add much to the Greek anyway. (I will go ahead with that if there are no objections.) --SpecMade (talk) 22:48, 22 October 2013 (UTC)[reply]

I have no problem with removing the Latin, since the Greek origin is probably more interesting. I do have the American Heritage Dictionary and just read the notes about how the etymologies were done; they did intend to provide their opinion of how the late Latin was pronounced. Maybe they got it wrong; I'm no expert on Latin. Jc3s5h (talk) 23:04, 22 October 2013 (UTC)[reply]

I do agree that you rightly reverted my edit, since it contradicted the source that had already been given, and I thank you for your vigilance. I have now changed it to be a bit more vague (and less controversial) and added another reference. There are simply more references to find for Classical Latin than for Late Latin, but if the only difference is the vowel lenght (which got less strict by Late Latin anyway), we are probably best off not to make any claim about that detail and not specify a particular stage of Latin. --SpecMade (talk) 01:17, 23 October 2013 (UTC)[reply]

Think some comment on this above, needs to be clearer about use in modern space ops, maneuver planning, antennae positioning, etc. Lycurgus (talk) 06:09, 6 July 2015 (UTC)[reply]

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The key to a definition is the verb "is" not "does" or "gives". The first sentence should be "... an ephemeris is _____". As written the question goes unanswered. Is an ephemeris a book? A chart? A set of numbers? A calculator? A pumpkin? Without a clear definition the rest of the article is a struggle to fully understand. Once one knows what an object *is*, then and only then is what it *does* or *gives* become relevant. ArtKocsis (talk) 18:42, 6 October 2017 (UTC)[reply]

It's a means by which a person or process can look up the positions of naturally occurring astronomical objects as well as artificial satellites in the sky at a given time or times. It could be a book, a chart, a set of numbers, or a calculator. Not a pumpkin. Jc3s5h (talk) 20:01, 6 October 2017 (UTC)[reply]

My point was that it needs to be clearly defined in the article. Most people are not going to read these talk pages to find what should be in the main article in the first place. (BTW, I'm relieved to know that it is not a pumpkin!) ;-) ;-)

Since "a means" is singular and "objects" is plural, does that mean one ephemeris (which, according to your definition, could be multiple pages or a book), only displays the coordinates(?) for multiple positions of a single object? Multiple positions of multiple objects? Multiple positions of multiple objects for multiple times? If so, then what is ephemerides?

It would help tremendously to have a readable example of a modern ephemeris with an explanation of the various entries and how to use it. The historical ones are interesting but unreadable. Also, where/how do ephemerides fit in with terrestrial (especially nautical), navigation? ArtKocsis (talk) 22:23, 6 October 2017 (UTC)[reply]

Typically, an ephemeris will provide positions for a substantial number of objects for at least a year, but possibly many centuries. Keep in mind that some almanacs could also be called ephemerides. For one example of where the plural would be useful, look at the article Jet Propulsion Laboratory Development Ephemeris. JPL has produced dozens of ephemerides, which differ due to more up-to-date data, a goal to be as accurate as possible over a shorter span of years vs. being reasonably accurate over many centuries, etc. Of course, these JPL ephemerides are computer models, not books. Jc3s5h (talk) 01:05, 7 October 2017 (UTC)[reply]

A working link found for Note 7 is https://www.aldebaran.cz/bulletin/2009_24/GAKVAB.pdf Drankinatty (talk) 05:58, 2 October 2020 (UTC)[reply]