William Herschel discovered NGC 5603 = H III-734 = h1800, along with NGC 5598, on 29 Apr 1788 (sweep 837) and noted "cF, pS.". John Herschel made two observations (first on 13 May 1828), calling this galaxy both pB and vF. His mean position matches UGC 9217. The MCG misidentifies this galaxy as NGC 5601. Brightest in a group.

400/500mm - 17.5" (5/15/99): fairly faint, fairly small, round, 0.7' diameter, even concentration to a brighter core and faint, stellar nucleus. Brightest in a group with NGC 5598 7' SW and NGC 5601 4.3' SSW. Also, a low surface brightness companion, UGC 9216, less than 3' NNW was not seen.

Notes by Steve Gottlieb