This image was taken with an ST-9E CCD camera thru Kopernik's 20-inch F/8.1 telescope. The field of view is about 8x8 arc minutes.
W. Hershel (1783): '...a beautiful cluster of extremely compressed stars, resembling M-53'
Admiral Smyth: 'A rich globular cluster of compressed stars of a lucid white tint, somewhat attenuated at the margin and clustering to a blaze in the center. Easily resolvable by moderate means.'
Burnham's Celestial Handbook: "Globular star cluster... lying ....well north of the main mass of the star clouds of the Ophiuchus Milky Way. ....bright and easily located in good binoculars..... M-10 is a rich cluster of magnitude 7 with an extreme diameter of about 12 arc minutes and a bright compressed center. Partial resolution may be achieved with a good 6-inch or 8-inch telescope....."
Dreyer's description of NGC 6254 in his New General Catalog(NGC): "Remarkable! Globular cluster, bright, very large, round, gradually very much brighter middle, well resolved, stars of magnitude 10 to 15; = M10."
Several sources give the distance to M-10 as 16,300 light years, and at that distance the true diameter would be 85 light years. But Click here for the latest news on Globular Star Cluster distances and ages!!