E.E. Barnard discovered IC 2533 = D.S. 325 visually on 13 May 1890 using the 12-inch refractor at Lick Observatory. He noted "Indef. 12m. A 7 1/2m star 10' p and 5' S. His rough pointing (9h 56m -30.9 for 1890) lands 12'-14' from NGC 3095, NGC 3100 and IC 2533. Barnard has the note "= NGC 3100" in his notebook, but his description of the mag 7.5 star only fits IC 2533. Mag 7.2 HD 86765 is 7' preceding and 6' south of IC 2533. DeLisle Stewart recorded it from an Arequipa plate in 1900 and is credited in the IC.

400/500mm - 17.5" (3/28/87): moderately bright, small, almost round, strong bright core, possible stellar nucleus. Located 31' N of NGC 3095.

Notes by Steve Gottlieb