NGC 3312 is a large and highly inclined spiral galaxy located about 194 million light-years away in the constellation Hydra. The galaxy was discovered by astronomer John Herschel on March 26, 1835. It was later rediscovered by astronomer Guillaume Bigourdan on February 26, 1887. NGC 3312 was later listed and equated with IC 629 because the two objects share essentially the same celestial coordinates. NGC 3312 is the largest spiral galaxy in the Hydra Cluster and is also classified as a LINER galaxy.

300/350mm - 13.1" (2/18/04) - Costa Rica: moderately bright, moderately large, very elongated 3:1 N-S, 1.5'x0.5', weak concentration. Possible a brighter knot is at the north end or a star may be near the edge of the halo. Three stars are close SE including two mag 11/12 stars 2' SE and 3' ESE of center. In the core of AGC 1060 with NGC 3311/3309 5' NW.

13.1" (2/23/85): fourth of five in the core of AGC 1060. Moderately bright, small, stellar nucleus, elongated 2:1 NNW-SSE. NGC 3311 lies 4.8' NW. Located 7.0' NE of mag 6.8 SAO 179027.

400/500mm - 18" (4/9/05): moderately bright, moderately large, elongated 2:1 NNW-SSE. Contains a fairly bright, roundish core ~20" diameter with fainter extensions 1.2'x0.6'. The core steadily increases to a stellar nucleus. A small isosceles triangle of stars is close SE.

600/800mm - 24" (3/28/17): moderately to fairly bright, fairly large, elongated 5:2 N-S. Sharply concentrated with a reasonably large oval core (N-S). The diffuse halo extends roughly 2.0'x0.8' (largest in the cluster) with averted vision. A faint star, perhaps 15th magnitude, is superimposed just southeast of the core. The NGC 3309/3307 pair is 5' to 6' NW and NGC 3316 lies 8' ESE. Mag 4.9 HD 92036 is 9.5' NNE, but not in the field at higher power.