Édouard Stephan discovered NGC 2393 = St XIII-28 on 7 Feb 1885. His position matches UGC 3884 = PGC 21154.

300/350mm - 13.1" (2/23/85): extremely faint, similar in size to NGC 2388 but a lower surface brightness. Located 16' NE of NGC 2389. Last of 7 in the cluster.

400/500mm - 18" (1/13/07): very faint, fairly small, slightly elongated E-W, 0.6'x0.5', low even surface brightness. Located 16' NE of NGC 2389 in a cluster.

Notes by Steve Gottlieb