NGC 1721 explained

NGC 1721
Credit:	Kopernik Observatory & Science Center, Vestal NY
Epoch:	J2000
Constellation Name:	Eridanus
Ra:	^[1]
Z:	0.015010
H Radial V:	4 500 ± 9 km/s
Gal V:	4 388 ± 10 km/s
Dist Ly:	200Mly
Type:	(R')SAB0^0(s)
Size:	36.92 by 17.58 kpc

NGC 1721 is a lenticular galaxy (S0) located in the constellation Eridanus. It was discovered on the 10th of Nov 1885^[2] by Edward Emerson Barnard. This galaxy is a member of the NGC 1723 Group—consisting of NGC 1723 (the brightest member, 11.7-mag) and a close triplet of NGC 1721, NGC 1725 and NGC 1728.^[3]

NGC 1721 is a Dreyer Object (a now archaic astronomical term), meaning that it was included in the original New General Catalogue by JLE Dreyer.^[4]

Notes and References

1. Web site: NED results for object NGC 1721 . NASA/IPAC Extragalactic Database (NED) . March 15, 2012 .
2. Web site: cseligman.com.
3. Web site: NGC 1723 Group. DeepSkyPedia.
4. Observations of nebulae with the 36-inch refractor of the Lick Observatory – by S. W. Burnham (Publications of the Lick Observatory). 1894PLicO...2..168B. Burnham . S. W. . Publications of Lick Observatory . 1894 . 2 . 168 .