William Herschel discovered NGC 4578 = H II-15 = h1365 = h1366 on 18 Jan 1784 (sweep 86) and recorded "F, S. It is not cometic though pretty round; of the first class." JH made two observations which differed by 5' in declination, so he was uncertain if they refered to the same object. As a result, he included two GC designations which Dreyer combined in the NGC.

400/500mm - 17.5" (4/18/87): moderately bright, fairly small, oval 3:2 SW-NE, 1.5'x1.0', small bright core with possibly a stellar nucleus. A mag 10.5 star lies 4.1' W of center.

Notes by Steve Gottlieb