NGC 21 | |
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![]() NGC 21/NGC 29 (Sloan Digital Sky Survey) | |
Observation data (J 2000.0 epoch) | |
Constellation | Andromeda |
Right ascension | 00h 10m 46.9s[1] |
Declination | +33° 21′ 10″[1] |
Redshift | 0.015911[1] |
Heliocentric radial velocity | 4770 ± 4 km/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 as NGC 29) is a spiral galaxy in the Andromeda constellation. It was discovered by German-British astronomer William Herschel on 26 November 1790. Lewis Swift observed it again in 1885, leading to its double listing in the New General Catalogue.