John Herschel discovered NGC 4558 = h1354 on 19 Apr 1827 and logged "vF; the nf of 2 (the p is II 380); a third suspected. His offset is 10 sec of RA east and 3' north of NGC 4556 (measured the same sweep). Unfortunately, his position falls very close to IC 3556, though d'Arrest measured two good positions so the NGC position is less than 1' off.

MCG and PGC misidentify this galaxy as NGC 4557 and misidentify IC 3556 as NGC 4558. See Harold Corwin's identification notes for more.

400/500mm - 18" (5/12/07): faint, very small, round, 20"-24" diameter, slightly brighter core. Symmetrically placed on the opposite side of a mag 13 located at the midpoint of NGC 4556 and NGC 4558. Located 5.2' NNE of NGC 4556 in a small group. IC 3556 lies 2' SE and appeared very faint, small, slightly elongated N-S, 20"x15". IC 3559 is 2.4' E, but with mag(B) = 16.6, it was only glimpsed knowing the exact location.

Notes by Steve Gottlieb