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| M54, A Globular Cluster, - this image cropped and reduced from the original photo, Click on photo above for a full frame full rez image. |
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M54 is a fairly bright but small globular cluster, but
because it is 30 degrees below the celestial equator, it is difficult to see
from the northern mid latitudes. It may be overlooked in binoculars or small
finder scopes. Even with a clear view and a large amateur scope its core
remains unresolved. The core appears to us to be only 2.1' in diameter, with
an intense nucleus of about 1', with the outlayers reaching out to 6' on
photos, or up to 9.1' at very long exposures. Another reason it is so
difficult to resolve is because its distance from us is estimated to be
about 87,000 light years. M54 can be found almost exactly between and in
line with the two bottom stars of the Teapot asterism. Because it is bright
but small it can easily be mistaken for a star. In 1994, the exciting discovery was made that M54 is probably not a member of our Milky Way at all, but of a newly discovered dwarf galaxy ! This galaxy is now called SagDEG, for Sagittarius Dwarf Elliptical Galaxy, and is one of the most recently discovered members of our local group of galaxies. M54 coincides with one of two major concentrations of the SagDEG galaxy, both of which are receding from us at a similar velocity (about 130 km/sec), and in the same direction. Because of it's great distance from us, about three times as distant as its two apparently close neighbors, M69 and M70., M54 would be one of the most luminous known globular clusters known to us, shining with a brilliance of about 850,000 suns, and outshown only by the spectacular Omega Centauri in our Milky Way. Also, its diameter would become nearly as large at about 300 light years. |
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10"
F6.3 Schmidt Cassegrain Telescope, (1600mm F.L.) Modified Canon
300D camera with IR-UV filter, placed at the scopes prime focus |