John Herschel discovered NGC 3311 = h3281 on 30 Mar 1835 and noted as "The following neb of a double one [with NGC 3309]." He actually noted both objects in his observation on 24 March, but didn't list the objects separately for that sweep.

300/350mm - 13.1" (2/18/04 - Costa Rica): fairly bright, fairly large, broad concentration, slightly elongated SSW-NNE. Outer halo increases to 2.0'x1.5' but has a slightly lower surface brightness than NGC 3309 as the core is not as concentrated. NGC 3312 is less than 5' SE and NGC 3308 is 7' NW.

13.1" (2/23/85): third of five in the core of AGC 1060 = Hydra I. Fairly faint, small, even surface brightness. Appears larger than NGC 3309 1.7' W but with a lower surface brightness. NGC 3312 lies 4.8' SE. Located 7.7' N of mag 6.8 SAO 179027.

600/800mm - 24" (3/28/17): fairly bright, fairly large, roundish core but slightly elongated halo, the brighter central region is relatively large, the outer halo extends ~1.5' (second largest in the central region). Forms a striking pair with NGC 3309 1.7' WNW. A mag 13.4 is 1.2' WNW (at the edge of NGC 3309's halo).

Notes by Steve Gottlieb