John Herschel discovered NGC 312 = h2363 on 5 Sep 1836 and noted "vF, S, R". On a later sweep he logged "F, S, R, 15", follows a star 12th mag on same parallel". The mag 12 star mentioned in the description is 2.5' W. His mean position from 2 observations is accurate.

600/800mm - 30" (10/13/15 - OzSky): at 394x; bright, fairly small, high surface brightness, 40"x30", sharply concentrated with an intense core. The halo is extended 4:3 or 5:4 WSW-ESE. A mag 11.3 star lies 2.4' W. NGC 312 is the furthest north in a group of 8 galaxies in a 25' string to the south. The galaxies share a common redshift of z = .026, implying a distance of ~350 million l.y. The closest companion is ESO 151-5 is 3' SSW. It appeared fairly faint to moderately bright, elongated at least 2:1 N-S, sharply concentrated with a small bright core and faint extensions ~40"x20". NGC 328 lies 10.6' SE and NGC 323 is 12' SSW.

Notes by Steve Gottlieb