NGC 21

NGC 21 (also known as NGC 29) is a spiral galaxy in the Andromeda constellation. It was discovered by William Herschel in 1790. Lewis Swift observed it again in 1885, leading to its double listing in the New General Catalogue.

NGC 21
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
NGC 21, UGC 100, PGC 767.