Wilhelm Tempel discovered NGC 5436, along with NGC 5437 and 5438, on 28 Jun 1883 while observing the NGC 5416 group. In the narrative portion of list VII he wrote "Since then I have repeatedly seen the new nebula in group III-56 and found 3 new nebula here; these three are in a line, 2'-3' away from each other and follow north near the [mag 9] star, the northernmost is quite bright." He did not measure positions and only a single rough position is given in the NGC for NGC 5436, 5437 and 5438. Harold Corwin notes the WH probably saw at least one of these three (H III-57 = NGC 5446) and NGC 5438, the northernmost galaxy, is the most likely (noted by Tempel as the brightest).

400/500mm - 17.5" (6/4/94): faint, very small, faint halo with an abrupt brighter core. Located 5.2' ENE of mag 8.8 SAO 120258. First of three in trio with NGC 5437 3.4' SSE and NGC 5438 2.8' NNE in the NGC 5416 galaxy cluster.

Notes by Steve Gottlieb