DeLisle Stewart discovered IC 4635 = D.S. 438 on a plate taken 17 Aug 1900 at Harvard's Arequipa Station. He noted "vF, eS, cbM+"

600/800mm - 25" (10/15/17 - OzSky): at 244x and 397x; faint, moderately large, edge-on 5:1 NNW-SSE, ~1.2'x0.25', low surface brightness. A distracting mag 13 star is superimposed at or very close to the west edge of the south end and only the portion of the galaxy north of this star was obvious and a ghostly extension south of the star was only suspected. The nucleus of the galaxy is a very small brighter spot 0.6' N of the superimposed star. A mag 10 star lies 4.3' ESE. IC 4635 is the second in a trio (KTS 54) with IC 4633 6.7' SW and ESO 044-010 16' NE. Like IC 4633, this galaxy resides among streams of very faint galactic nebulosity (IFN) in a very photogenic field.

Notes by Steve Gottlieb