William Herschel discovered NGC 4020 = H II-725 = h1045 on 3 Feb 1788 (sweep 805) and recorded "pB, E, mbM, about 2' long from sp to nf, but nearer to the meridian." John Herschel recorded "Not vF; bicentral or elongated; vgbM to a central axis pos = 199.5°, or pos of the two centres = 19.5°; 14" long and 25" br." The Slough Catalogue has a typo; read H. II-725 for H. II-275. He corrected the error in the GC. Bindon Stoney, observing on LdR's 72" on 26 Apr 1851, not "Bicentral appearance very indistinct. Light mottled, E ssp-nnf."

400/500mm - 17.5" (5/4/02): fairly faint, moderately large, elongated 2:1 SSW-NNE, 1.8'x0.9', broad concentration but no well-defined core. A mag 10.5 star lies 3.1' WSW.

Notes by Steve Gottlieb