William Herschel discovered NGC 2578 = H III-902 = h3121 on 8 Mar 1793 (sweep 1034) and logged "vF, lE, bM, resolvable." JH, observing from the Cape of Good Hope, recorded "vF, R, gbM, in a field full of Milky Way stars." Both Herschels' positions are accurate. JH missed the companion described in my observation.

400/500mm - 17.5" (4/6/91): faint, small, oval 3:2 WSW-ENE, broad concentration, faint stellar nucleus at moments, in a fairly rich star field. Located 2.5' NNW of a mag 11 star. Forms a pair with MCG -02-22-003 3' SE (not seen) which is close following the mag 11 star.

600/800mm - 24" (2/16/15): at 322x; moderately bright and large, oval E-W, 1.0'x0.7', fairly strong concentration with a well-defined bright core and much fainter halo. A mag 15 star is superimposed on the northeast side [24" from center]. Situated in a rich star field with a mag 10.5 star 2.5' SE.

Forms a pair with MCG -02-22-003 = PGC 23449, which lies just 50" E of the mag 10.5 star and 3.0' SE of NGC 2578. It was seen initially at 322x and at 450x appeared faint to fairly faint, small, slightly elongated ~E-W, ~20"x15".

Notes by Steve Gottlieb