NGC 21 explained

NGC 21
Epoch:	J 2000.0
Constellation Name:	Andromeda
Z:	0.015911^[1]
Dist Ly:	234 ± 29 Mly ^[2]
Type:	SAB(s)bc
Appmag V:	+12.8
Absmag V:	-20.75^[3]
Size V:	1,2′ × 0,59′

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.

NGC 7831 Group

According to A.M. Garcia, NGC 21 is a member of the NGC 7831 group (also known as LGG 1), which contains at least 18 galaxies, including NGC 13, NGC 20, NGC 39, NGC 43, NGC 7805, NGC 7806, NGC 7819, and NGC 7836.^[4]

External links

• • Wikisky image of NGC 29

Notes and References

1. Web site: NASA/IPAC Extragalactic Database . Results for NGC 0021 . 2010-05-03.
2. Web site: Distance Results for NGC 0021 . NASA/IPAC Extragalactic Database . 2010-05-03.
3. Web site: The galaxy NGC 21.
4. 1993A&AS..100...47G . General study of group membership. II. Determination of nearby groups . Garcia . A. M. . Astronomy and Astrophysics Supplement Series . 1993 . 100 . 47.