William Herschel discovered NGC 4651 = H II-12 = h1409 on 30 Dec 1783 (sweep 74) and recorded "vF, pL, almost R but not cometic, about 3/4 degree sp 27 Coma Ber. CH's reduction is a poor match (common in his early sweeps), but his offset from 27 Com matches. JH made 4 observations and measured a fairly accurate position.

300/350mm - 13.1" fairly bright, slightly elongated, broad moderate concentration, fainter extensions ~E-W.

400/500mm - 18" (4/10/04): bright, large, elongated 3:2 ~E-W. Well-concentrated with a very bright, elongated 1.0'x0.6' core which increases to the center. Surrounding the core is a large, low surface brightness halo increasing the size to at least 2.5'x1.4' and perhaps 3'x2'.

Notes by Steve Gottlieb