R.J. Mitchell discovered NGC 3989 at Birr Castle on 27 Apr 1854 and was labeled "Xi" on the later constructed sketch. Although a micrometric position was not measured, the identification with CGCG 127-111 = PGC 37599 is certain.

400/500mm - 17.5" (3/19/88): extremely faint, very small, round. Located 1.2' E of a mag 10 star. Member of the NGC 4007 group with NGC 3987 2.5' SSW and NGC 3993 2.7' ENE.

600/800mm - 24" (3/22/14): very faint, small, round, 15" diameter. Located 1.2' E of a mag 10.5 star and 2.6' NNE of NGC 3987. NGC 3993 is 2.6' E.

Notes by Steve Gottlieb