William Herschel discovered NGC 3923 = H I-259 = h3366 on 7 Mar 1791 (sweep 998) and logged "cB, pL, gbM, lE, the brightness takes up a large space of it." His position is at the southwest edge of the galaxy. John Herschel made two observations, first logging "B, pL, lE, glbM, 80" long, 50" broad, resolvable."

200/250mm - 8" (5/21/82): bright, moderately large, elongated SW-NE, small bright nucleus. NGC 3904 lies 40' SW.

400/500mm - 18" (4/29/06): very bright, fairly large, elongated 3:2 SW-NE, ~2.5'x1.5'. Well-concentrated with a very bright elongated core that increases to a stellar nucleus. The relatively fainter halo increases in size with averted vision. This well-studied galaxy is surrounded by concentric gaseous shells of material.

600/800mm - 24" (4/13/18): at 200x; very bright, large, oval ~2:1 SW-NE. Sharply concentrated with a very bright and very small core that seems mottled, highlighted by a stellar nucleus. A very faint star is situated at the southwest edge of the core. The core is surrounded by a large, much fainter oval halo that increases in size with averted vision and extends at least 4'x2'.

Supernova 2018aoz, discovered on April 2 (11 days ago) was surprisingly bright at mag ~13.0 and very easy to identify 3.7' N of center. It was clearly brighter than a mag 13.5 star superimposed at the southwest edge of the halo.

Notes by Steve Gottlieb