William Herschel discovered NGC 4783 = H I-136, along with NGC 4782, on 27 Mar 1786 (sweep 548). See notes on NGC 4782.

200/250mm - 8" faint, very small. The pair is elongated SSW-NNE.

400/500mm - 17.5" (3/23/85): moderately bright, very small, round. Forms an interesting contact pair with NGC 4782 0.6' SSW within a common halo.

900/1200mm - 48" (4/21/17): NGC 4783 is the northern galaxy of a striking contact pair with NGC 4783 [39" between centers]. The merged halos of the two galaxies form a dogbone or dumbbell outline. At 813x, it appeared bright, moderately large, round, ~40" diameter, well concentrated with a small bright nucleus. A mag 14.5 star is 30" SE of center (just outside the combined halos). An extremely faint "knot", roughly 5" diameter, is at the northwest edge of the halo. Checking later, I found this is a nearly stellar galaxy, catalogued in HyperLeda as PGC 5065968 and in NED as [QRW96] 073.

Notes by Steve Gottlieb