Messier Index/M10
| M10 | |
|---|---|
 | |
| Observation data (J2000 epoch) | |
| Class | VII |
| Constellation | Ophiuchus |
| Right ascension | 16h 57m 08.99s[1] |
| Declination | -04° 05′ 57.6″[1] |
| Distance | 14.3 kly (4.4 kpc) |
| Apparent magnitude (V) | 6.4[1] |
| Apparent dimensions (V) | 20′.0 |
| Physical characteristics | |
| Mass | kg ( M) |
| Radius | 41.6 ly [2] |
| Other designations | NGC 6254[1] |
Messier 10 or M10 (also designated NGC 6254) is a w:globular cluster in the w:constellation of w:Ophiuchus.
The object was discovered by w:Charles Messier on w:May 29 w:1764, who cataloged it as number 10 in his list. He described it as a "w:nebula without stars", but later study revealed it as a globular cluster of thousands of stars.
M10 has an apparent diameter of some 20 w:arcminutes, about two-thirds of the w:apparent diameter of the w:Moon. Viewed through medium-sized w:telescopes it appears about half that size (8' to 9'), as its bright core is only 35 light-years across. M10 has a spatial w:diameter of 83 w:light-years and is estimated to be 14,300 light-years away from Earth. Four w:variable stars have been discovered in this cluster.