M28 is a globular cluster located 17,900 light-years away from Earth in the constellation Sagittarius. It was discovered by Charles Messier in 1764. With an apparent magnitude of 7.7, the cluster appears as a faint patch of light through a pair of binoculars. Large telescopes can resolve its individual stars more effectively. The month of August is the best time to view M28.
The cluster is most notable for being the first of its kind known to contain a millisecond pulsar: PSR B1821–24. This dense neutron star rotates rapidly (about once every three milliseconds) and emits radiation from its poles, which sweeps past Earth as the star spins, much like a beam of light from a lighthouse. This makes it appear to be pulsing to observers on Earth. PSR B1821–24 was discovered in 1986 using a radio telescope in England called the Lovell Telescope.
This Hubble image of M28’s center was assembled from observations taken at visible, infrared and ultraviolet wavelengths.
Credits: NASA, ESA, STScI, R. Buonanno (Universita di Roma Tor Vergata), K. Gebhardt (University of Texas at Austin), J. Grindlay (Harvard University), and F. Ferraro (Universita di Bologna)
The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain.
The SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use. [2]
{{Information |Description='''Messier 28 M28 is a globular cluster located 17,900 light-years away from Earth in the constellation Sagittarius. It was discovered by Charles Messier in 1764. With an apparent magnitude of 7.7, the cluster appears as a f...