William Herschel discovered NGC 4782 = H I-135, along with NGC 4783, on 27 Mar 1786 (sweep 548) and recorded "Two, both cB, R, cS, mbM in the direction of the meridian., nearly within 1' of each other, and the chevelure [halo] mixisng." His position is accurate (landing on the southern galaxy). See Harold Corwin's NGC notes on problems with the identifications of the two components.

200/250mm - 8" (3/28/81): faint, very small. Contact pair with NGC 4783 oriented SSW-NNE.

400/500mm - 17.5" (3/23/85): moderately bright, very small, round. Forms an extremely close contact pair with NGC 4783 in a common halo 0.6' NNE of center.

900/1200mm - 48" (4/21/17): at 813x; bright, moderately large, slightly elongated, ~45" diameter, well concentrated with a small bright core. Forms a striking N-S contact pair (halos form a dumbbell or dogbone outline) with NGC 4783 [40" between centers]. A mag 14.5 star is 30" NW, barely outside the halo. A 16th magnitude star is within the northeast side of the halo. NGC 4782/83 are the brightest in a large group that includes NGC 4794 9' ESE and NGC 4792 8' NE.

Notes by Steve Gottlieb