NGC 251 explained

NGC 251
Epoch:	J2000
Constellation Name:	Pisces
Ra:	^[1]
Z:	0.015184^[2]
H Radial V:	4552 km/s
Type:	Sc
Size:	^[3]
Appmag B:	14.6^[4]
Size V:	2.4 × 1.9
Names:	UGC 490, MGC+03-03-003, PGC 2806

NGC 251 is a spiral galaxy in the constellation of Pisces. It was discovered on October 15, 1784, by Frederick William Herschel.

One supernova has been observed in NGC 251: SN 2023rky (type II, mag. 18.6).^[5]

Notes and References

1. 10.1086/498708 . Skrutskie . Michael F. . Cutri . Roc M. . Stiening . Rae . Weinberg . Martin D. . Schneider . Stephen E. . Carpenter . John M. . Beichman . Charles A. . Capps . Richard W. . Chester . Thomas . Elias . Jonathan H. . Huchra . John P. . Liebert . James W. . Lonsdale . Carol J. . Monet . David G. . Price . Stephan . Seitzer . Patrick . Jarrett . Thomas H. . Kirkpatrick . J. Davy . Gizis . John E. . Howard . Elizabeth V. . Evans . Tracey E. . Fowler . John W. . Fullmer . Linda . Hurt . Robert L. . Light . Robert M. . Kopan . Eugene L. . Marsh . Kenneth A. . McCallon . Howard L. . Tam . Robert . Van Dyk . Schuyler D. . Wheelock . Sherry L. . The Two Micron All Sky Survey (2MASS) . The Astronomical Journal . 1 February 2006 . 131 . 2 . 1163–1183 . 2006AJ....131.1163S . 18913331 . 0004-6256 . free .
2. Web site: NED results for object NGC 0251. National Aeronautics and Space Administration / Infrared Processing and Analysis Center. 5 May 2017.
3. POSS1 103a-O values used.
4. NGC 251. 5 May 2017.
5. https://www.wis-tns.org/object/2023rky Transient Name Server entry for SN 2023rky.