Lewis Swift discovered NGC 5591 = Sw. III-82 on 4 Jun 1886 and recorded "eF; S; R; pB star near south-following." His position is 8 sec of RA too far west and 2.2' too far south though his comment "pB * near south-following" secures the identification.

400/500mm - 17.5" (5/15/99): faint, fairly small, elongated 5:2 ~E-W, 1.2'x0.5', slightly brighter core. A mag 11 star lies 2.7' SE. NGC 5587 lies 13' NNW. Either the pair was unresolved or I only viewed the brighter western component of this disturbed double system.

600/800mm - 24" (6/15/15): at 375x; the brighter western component of this merged, interacting double system appeared fairly faint, fairly small, elongated 3:2 E-W, roughly 0.6'x0.4', brighter core, fairly low surface brightness. The attached eastern component (PGC 93125) is elongated 5:2 E-W, ~0.5'x0.2' and contains a small, slightly brighter nucleus or knot, 6"-8" in diameter. The two nuclei are 22" apart (measured on the DSS2).

Notes by Steve Gottlieb