| NGC 21 | |
|---|---|
 NGC 21/NGC 29 (Sloan Digital Sky Survey) | |
| Observation data (J 2000.0epoch) | |
| Constellation | Andromeda |
| Right ascension | 00h 10m 46.9s[1] |
| Declination | +33° 21′ 10″[1] |
| Redshift | 0.015911[1] |
| Heliocentric radial velocity | 4,770 ± 4km/s[1] |
| Distance | 234 ± 29 Mly (71.7 ± 8.9 Mpc)[2] |
| Apparent magnitude (V) | +12.8 |
| Absolute magnitude (V) | -20.75[3] |
| Characteristics | |
| Type | SAB(s)bc |
| Apparent size (V) | 1.2′ × 0.59′ |
| Other designations | |
| IRAS 00082+3304,NGC 29,UGC 100,MCG +05-01-048,PGC 767,CGCG 499-066[1] | |
NGC 21 (also known asNGC 29) is aspiral galaxy in theAndromeda constellation. It was discovered byGerman-British astronomerWilliam Herschel on 26 November 1790.Lewis Swift observed it again in 1885, leading to its double listing in theNew General Catalogue.
According to A.M. Garcia, NGC 21 is a member of theNGC 7831 group (also known asLGG 1), which contains at least 18 galaxies, includingNGC 13,NGC 19,NGC 20,NGC 39,NGC 43,NGC 7805,NGC 7806,NGC 7819, andNGC 7836.[4]
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