|Right Ascension||18 : 55.1 (h:m) |Declination||-30 : 29 (deg:m)
|Visual Brightness||7.6 (mag) |Apparent Dimension||12.0 (arc
min) Discovered 1778 by Charles Messier. Messier 54 (M54, NGC
6715) is a quite conspicuous globular cluster, although Charles
Messier, who discovered it on July 24, 1778, describes it as
"very faint" from his location in Paris (Kenneth Glyn Jones
erroneously mis-translated Messier's description as "very bright
nebula," and this error found its way to Kepple and Sanner's
Night Sky Ovserver's Guide). William Herschel could resolve its
outer regions in 15th and a few 14th magnitude stars. It is not
easy to resolve, however. As its concentration class III
indicates, this cluster is comparatively concentrated. Its
bright core is only 2.1' in diameter, with an intense nucleus of
about 1', while the outlayers reach out to 6' on photos, or even
to 9.1' at very long exposures. The second edition of
Uranometria 2000.0 even gives a diameter of 12.0 arc minutes.
The apparent magnitude of the brigh