R.J. Mitchell discovered NGC 7435, along with NGC 7433, on 12 Oct 1855 while examining the field of NGC 7436 at Birr Castle. The identification is certain based on the diagram and sketch in Plate V, including a star close northwest. The NGC position is 1' due south, instead of southwest of NGC 7436. Heinrich d'Arrest also measured the position twice in September 1865, although Dreyer only credited d'Arrest's observation of NGC 7433.

The NGC position falls very close to MCG +04-54-007 = LEDA 1763030, and Francis Pease identified this galaxy as NGC 7435 in the 1920 paper "Photographs of nebulae with the 60-inch reflector, 1917-1919".

400/500mm - 17.5" (8/25/95): very faint, very elongated 3:1 NNW-SSE, 0.6'x0.2', no concentration. A mag 15 star is at the NNW end. In a tight group just 1.0' SW of NGC 7436.

17.5" (9/2/89): very faint, very elongated NW-SE. A mag 15 star is attached at the NNW end 17" from center. Located 1.0' SW of NGC 7436 in a group.

600/800mm - 24" (7/20/12): faint or fairly faint, small, very elongated 3:1 NNW-SSE, 24"x8". A mag 15 star is attached at the NNW tip. This close companion to NGC 7436 is situated just 1.0' SW of center.

900/1200mm - 48" (10/26/16): at 610x; fairly bright, fairly small, elongated 5:2 NNW-SSE, 30"x12", small brighter nucleus. A mag 15 star is on the NNW end [17" from center]. Situated 0.9' SW of NGC 7436 in the center of the cluster.

Notes by Steve Gottlieb