Globular Star Cluster M-10 (NGC 6254)

Description of M-10 in The Deep Sky Field Guide to Uranometria 2000 (c) Willmann-Bell, Inc.:

Brightest stars = magnitude 12.0
horizontal branch stars magnitude = 14.7
Concentration: 7 (scale 1{dense} to 12{loose})


Charles Messier (May 29th, 1764): 'Nebula without star in the belt of Ophiuchus. Fine and round..... Reported on 2nd chart of... comet of 1769.' Hand written notes in Messier's copy of his catalog include the following: "Reviewed 6th March, morning, 1781" "always fine." "Reviewed 10th March, morning, 1790."

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!!

• M-10, NGC 6254
• Magnitude: 6.6
• Constellation: Ophiuchus
• RA: 16h 57m 06.0s
• Dec: -04° 06' 00" Epoch 2000
• Size: (mins) 8
• Classification: Globular Cluster
  

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George Normandin, KAS

October 10th, 2002