William Herschel discovered NGC 4939 = H II-561 = h3458 on 25 Mar 1786 (sweep 546) and recorded "pB, pL, R, vgmbM." His position matches MCG -02-33-104 = PGC 45170. JH reported "pF; L; R; gpmbM; 60"."

400/500mm - 17.5" (5/17/90): moderately bright, fairly large, large low surface brightness oval halo 2:1 SSW-NNE, increases to a brighter core. A mag 15 star is 1.4' NW of center.

Notes by Steve Gottlieb