Globular Cluster Messier 10
History
The globular cluster Messier 10 was discovered by Charles Messier on May 29, 1764. He wrote: «Nebula without a star, in the belt of the serpent-bearer, next to the 30th star of this constellation, sixth magnitude after Flamsteed. This nebula is beautiful and round; it was difficult to see with an ordinary telescope of three feet [focal length].» [281]
Physical Properties
M 10 forms an interesting pair with its neighbor M 12. According to distance estimates, M 10, at 16'000 to 22'000 light years, is closer than the large globular cluster M 13 in the constellation Hercules. The integrated spectral type of M 10 is given as G0. The radial speed of approx. 72 km/s is relatively low compared to other globular clusters. [4]
| Designation | NGC 6254 |
| Type | GCL (VII) |
| Right Ascension | 16h 57m 08.9s |
| Declination | -04° 05' 56" |
| Diameter | 20.00 arcmin |
| Visual magnitude | 6.6 mag |
| Dreyer Description | ! globular, B, vL, R, gvmbM, rrr, st 10…15 |
| Identification | M 10, GCL 49 |
Finder Chart
The globular cluster Messier 10 is located in the constellation Serpent Bearer (Ophiuchus) near the 4.82 mag star 30 Ophiuchi. It can best be observed in the months of May to July.
