John Herschel discovered NGC 3309 = h3280 on 24 Mar 1835 and noted "B: L; double [with NGC 3311]." Less than a week later he added "A double nebula, or rather two distinct nebulae near together. By diagram, both pL, R, pos about 10° np or sf, and nearly equal."

300/350mm - 13.1" (2/18/04 - Costa Rica): fairly bright, moderately large, well-concentrated with a bright 40" core, halo increases with averted from 1.2'x1.0' to 1.5'x1.2' oriented SW-NE. Forms a pair with NGC 3311 1.7' ESE in the core of AGC 1060.

13.1" (2/23/85): moderately bright, small, round. A mag 13.5 star is at the east edge. Forms a close pair with NGC 3311 1.7' E. Second of five in the core of AGC 1060.

600/800mm - 24" (3/28/17): fairly bright, moderately bright, slightly elongated, ~1.2'x1.0', contains a bright core that increases to a stellar nucleus. Highest surface brightness core of the main galaxies in the central region of the cluster and noticeably higher than NGC 3311 just 1.7' ESE. A mag 13.4 star is at the east edge (30" from center) and a mag 15 star is close WSW [48" from center].

Notes by Steve Gottlieb