William Herschel discovered NGC 3320 = H II-745 = h732 on 1 Apr 1788 (sweep 822) and recorded "cF, pS, E. Mixed with some stars visible, but probably not belonging to it. A pL star north and a little following the nebula." His position is 5' north of UGC 5794 (similar offset as other nebula in the sweep). John Herschel made two observations, recording on 7 Mar 1831 (sweep 329), "F; mE; between a *10m and one of 14 m."

400/500mm - 17.5" (2/8/91): moderately bright, fairly small, oval 2:1 SSW-NNE, broad concentration. A mag 13.5 star is at the SSW end 40" from center and a mag 11 star is off the NNE end 2.1' from center.

Notes by Steve Gottlieb