William Herschel discovered NGC 2939 = H III-4 = h614 on 18 Jan 1784 (sweep 82) and recorded (full text) "A nebula. About 2/3 degree prec. & about 10' foll of 14 Leonis, a very faint nebula or cl of suspected stars. A triangle is situated just north of it, but the nebula is so faint that is best to be seen when the stars are drawn out of the field. These 3 or 4 stars are visible in the finder in the shape of a small nebula." His position (from sweep 534 on 3 Mar 1786) is 3' northwest of UGC 5134 = PGC 27451.

400/500mm - 17.5" (2/20/88): fairly faint, fairly small, elongated 2:1 NNW-SSE, bright core. Forms a pair with NGC 2940 5.6' N.

600/800mm - 24" (2/8/18): at 375x; moderately bright and large, very elongated 7:2 NNW-SSE, ~1.4'x0.4'. Contains a brighter core with a mag ~14 star attached at its southeast edge! The extensions fade out at the tips. In a trio with NGC 2940 5.6' N and IC 548 5.5' SE. NGC 2939 is part of the NGC 2911 group (LGG 177 at z = .01), which includes NGC 2913 and 2914.

Notes by Steve Gottlieb