William Herschel discovered NGC 5273 = H I-98 = h1664 on 1 May 1785 (sweep 405) and recorded "cB, pL, mbM, R. The brightness diminishing very gradually." JH made three observations, recording on sweep 331 "B; R; first g and the psbM; 50"." Nearby NGC 5276 was discovered at Birr Castle.

200/250mm - 8" (5/21/82): faint, small, small bright nucleus with a fainter outer halo.

400/500mm - 17.5" (6/7/97): moderately bright, fairly large, elongated 4:3 N-S, ~2.5'x2.0'. Fairly low surface brightness halo contains a well-defined core gradually increasing to a stellar nucleus. Forms a pair with NGC 5276 3.3' SE.

Notes by Steve Gottlieb