William Herschel discovered NGC 3163 = H II-640 = h681, along with NGC 3158, on 17 Mar 1787 (sweep 713) and logged "F, vS, r. 300x showed the same." Caroline's reduction is within 30" of the core of this galaxy.

300/350mm - 13.1" (2/25/84): faint, small, round. Third of three in a string and the second brightest in a group.

400/500mm - 17.5" (3/23/85): fairly faint, small, round, bright core. Brightest and third of three with NGC 3161 1.5' W and NGC 3159 2.7' W.

Notes by Steve Gottlieb