E.E. Barnard discovered IC 4536 on 14 May 1888 with the 12-inch refractor at Lick Observatory and recorded (from his logbook) "vF, L, roundish, a faint star on np edge, a faint star nr sf edge. It follows a bright star by 1 field." The bright star is mag 6.9 HD 134812, situated 13' ESE. His sketch (in his logbook) and description is a perfect match.

600/800mm - 24" (6/23/17): fairly faint, large, roundish, ~1.2' diameter, low surface brightness, slightly brighter core. A mag 14.5-15 star is at the west edge. The surface brightness is a bit uneven or mottled but I didn't notice any distinct HII knots. Two mag 10 and 11 stars are 5' SW and 5' N, respectively. IC 4536 is located 12.5' ESE of mag 6.9 HD 134812.

Notes by Steve Gottlieb