R.J. Mitchell discovered NGC 3639 on 21 Jan 1855 with LdR's 72" and logged "about 15' following [NGC 3626] and a little north is a neb. S, R, pF, vlbM." Dreyer added the comment "d'Arrest could not see [NGC 3639], perhaps the observation from 1855 was of some other neb. in this neighborhood." But the position matches UGC 6374 = PGC 34819, so there is no question regarding the identification, altlhough UGC, CGCG and MCG do not label this galaxy as NGC 3639.

400/500mm - 16" LX200 (4/14/07): faint, small, elongated 4:3 ~N-S, occasional very faint stellar nucleus with direct vision. Located 2' N of a mag 12 star.

Notes by Steve Gottlieb