NGC 6638 | |
---|---|
Observation data ( J2000 epoch) | |
Class | VI |
Constellation | Sagittarius |
Right ascension | 18h 30m 56.2s |
Declination | −25° 29′ 45″ |
Distance | 31.3 ± 1.6 kly (9.6 ± 0.5 kpc) [1] |
Apparent magnitude (V) | 9.5 |
Apparent dimensions (V) | 2′ |
Physical characteristics | |
Mass | 1.89×105 [1] M☉ |
Other designations | GCl 95, C 1827-255 [2] |
NGC 6638 is a globular cluster in the constellation Sagittarius. It is magnitude 9.5 and diameter 2 arc minutes, class VI. It is a half degree east of Lambda Sagittarii. It is a member of the Milky Way. [3]
The globular cluster was discovered in 1784 by the astronomer William Herschel with his 18.7-inch telescope and the discovery was later entered in the New General Catalogue.