John Herschel discovered NGC 3135 = h672 on 19 Mar 1828 (sweep 139) and noted "F; R: gbM; 25"." His position matches UGC 5486. It was searched for once at Birr Castle and not found. Herschel mentioned in the General Catalogue notes that he checked the sweep and reductions and found all correct.

400/500mm - 17.5" (4/15/99): faint, fairly small, elongated 3:2 E-W, 0.8'x0.5', little or no concentration. Bracketed by two mag 12.5 stars 2.2' E and 2.1' NW.

Notes by Steve Gottlieb