Édouard Stephan discovered NGC 668 = St XI-2 on 4 Dec 1880 with the 31" reflector at the Marseille Observatory and recorded "pF; pS; R; gbM". His position is accurate.

400/500mm - 17.5" (11/27/92): fairly faint, slightly elongated SW-NE, broadly concentrated halo, small bright core. Located 2.5' W of a mag 10.5 star at the NW edge of AGC 262 galaxy cluster.

Notes by Steve Gottlieb