| Observation data: J2000 epoch | |
|---|---|
| Class: | XI |
| Constellation: | Sagittarius |
| Right ascension: | 19h 39m 59.40s[1] |
| Declination: | -30° 57′ 43.5″[1] |
| Distance: | 17.3 kly (5.3 kpc) |
| Apparent magnitude (V): | +7.42[1] |
| Apparent dimensions (V): | 19′.0 |
| Physical characteristics | |
| Mass: | ( M☉) |
| Radius: | 48 ly[2] |
| VHB: | |
| Estimated age: | |
| Notable features: | |
| Other designations: | M55, NGC 6809, GCl 113[1] |
| See also: Globular cluster, List of globular clusters | |
Messier 55 (also known as M55 or NGC 6809) is a globular cluster in the constellation Sagittarius. It was discovered by Nicolas Louis de Lacaille in 1751 and catalogued by Charles Messier in 1778. M55 is at a distance of about 17,300 light-years away from Earth. Only about half a dozen variable stars have been discovered in M55.
