E.E. Barnard visually discovered IC 2166 on 6 Oct 1888 with the 12-inch refractor at Lick Observatory. He noted "After visitors left found a new nebula. 1' following faint star, 3' preceding a double (1.5" or 2"). A small star following the double." He made a rough sketch in his notebook. His RA was 5 minutes too large, but the description and sketch clearly apply to UGC 3463.

400/500mm - 17.5" (3/8/97): fairly faint, diffuse glow with little concentration, although appears asymmetric. Moderately large, 2.0'x1.2', elongated NW-SE. Possibly up to 2.5' major axis with averted vision. A mag 13.5 star is at the west edge. An easy mag 10/12 pair [at 24" separation] lies 3' E. A 50" string of three mag 13 stars 4' NW is collinear with the galaxy.

Notes by Steve Gottlieb