Édouard Stephan discovered NGC 621 = St XIII-10 on 24 Nov 1883 with the 31" reflector at the Marseille Observatory and noted "vF, eS, R, bM and nucleus". His position is accurate.

400/500mm - 17.5" (12/23/89): faint, small, almost round, broad concentration. Located 2' SW of a mag 10.5 star and 7' S of mag 8.4 SAO 54831.

Notes by Steve Gottlieb