William Herschel discovered NGC 3738 = H II-783 on 14 Apr 1789 (sweep 920) and recorded "pB, pL, bM." His position matches UGC 6565.

300/350mm - 13.1" (3/24/84): fairly bright, almost even surface brightness.

400/500mm - 17.5" (3/19/88): fairly bright, moderately large, elongated 3:2 NNW-SSE although has an irregular appearance. Sharper edge on the west side and more curved on the east side. Two mag 10/11 stars are 2.4' NE and 4.0' ENE of center. NGC 3756 lies 15' SE.

600/800mm - 24" (5/27/17): at 200x; bright, large, elongated 3:2 NNW-SSE, ~2.0'x1.3', noticeably mottled or knotty appearance. Broad concentration but no defined core or nucleus. A brighter knot (HII complex?) is on the northwest side. A chain of bright stars begins at a mag 10.5 star 2.5' NE of center and extends southeast. NGC 3756 is 16' SE.

Notes by Steve Gottlieb