Édouard Stephan discovered NGC 7318 = St VIIIa-20 on 23 Sep 1876. He didn't resolved the pair, so the two components are often called NGC 7318A and 7318B. Harold Corwin carefully re-reduced his offsets and found he measured the brighter western component, although his position is just off the nucleus of the eastern component. Shapley and Ames mentioned NGC 7318 is "bi-nuclear and probably represents two interpenetrating system" in 1930BHarO.878....6S. The group is also referred to as "Stephan's Quintet".

100/150mm - 6" (6/25/04): extremely faint, glimpsed intermittently at 105x and 140x, along with NGC 7320 using a 6" mask. This double system was unresolved.

200/250mm - 8" (6/27/81 and 8/28/81): extremely faint, small. This double galaxy appears as a single object.

300/350mm - 13.1" (9/29/84): faint, elongated, two stellar nuclei are resolved in good seeing.

400/500mm - 17.5" (9/14/85): the western member of this double galaxy in Stephan's quintet is moderately bright, elongated ~E-W. The eastern member is moderately bright, elongated ~E-W. This double system appears as two stellar nuclei within a common elongated halo. The three other members are NGC 7317 1.6' SW, NGC 7320 1.9' SE and NGC 7319 1.5' NE.

Notes by Steve Gottlieb