William Herschel discovered NGC 4591 = H III-504 = h1372 on 2 Feb 1786 (sweep 521) and noted "vF, vS." CH's reduction is less than 1' south of UGC 7821. NGC 4577 = H III-13 is possibly an earlier observation. See that number.

400/500mm - 18" (4/10/04): fairly faint, fairly small, elongated 5:2 SW-NE, 0.7'x0.3', weak concentration.

Notes by Steve Gottlieb