Heinrich d'Arrest discovered NGC 931 on 26 Sep 1865 with the 11" refractor at Copenhagen. His position (mean of 2 observations) is on the east edge of UGC 1935 = PGC 9399.

400/500mm - 17.5" (12/23/92): fairly faint, moderately large, very elongated 3:1 WSW-ENE, 1.5'x0.5', broad concentration, faint stellar nucleus. Several brighter stars are in the field including a pair of mag 10 stars 6' NW and 10' N. NGC 940 lies 25' NE.

600/800mm - 24" (11/24/14): at 200x and 375x; moderately bright and large, thin edge-on 5:1 WSW-ENE, 1.5'x0.3', brighter core, sharp stellar nucleus. LEDA 212995, a very close (physical) companion, is at the north edge just 18" from center. At 375x, it appeared as an extremely faint and small glow, ~6" diameter.

Notes by Steve Gottlieb