William Herschel discovered NGC 3237 = H III-631 = h709 on 18 Mar 1787 (sweep 716) and noted "vF, vS. With 300 the same." Caroline's reduced position is 6' SSE of UGC 5640, but there are no other nearby candidates. On 18 Mar 1831 (sweep 335) John Herschel reported, "pF; R; S; pgbM; 10-12" dia." His position is marked as very uncertain, but his dec is just 1' south of UGC 5640.

400/500mm - 17.5" (4/13/02): fairly faint, fairly small, round, 0.8' diameter, brighter core. An uneven mag 12/14 double is 3' N and trailing from this pair is a string of three mag 10.5-11.5 (total length including double of 10').

Notes by Steve Gottlieb