Heinrich d'Arrest discovered NGC 4990 on 23 Mar 1865 with the 11-inch refractor at Copenhagen, while observing NGC 4989 located 7.5' south. His position (measured on two nights) matches PGC 45608 and he mentions the mag 12-13 star that follows by 9 sec of RA.

400/500mm - 17.5" (5/17/90): faint, extremely small, round, fairly high surface brightness, stellar nucleus. Forms a pair with NGC 4989 7.4' S.

Notes by Steve Gottlieb