William Herschel discovered NGC 5532 = H III-47 = h1765 on 15 Mar 1784 (sweep 175) and noted "vF, r. I see two or three stars in it." His position was 1.8' too far northwest. One of WH's "stars" is very possibly the companion at the south-southeast edge that I picked up. JH has a single observation and measured an accurate position. On 9 May 1825 (sweep 4), John Herschel measured an accurate position and called it "F, round, gbM."

There are several very faint galaxies nearby on the DSS - Could this be a background cluster?

400/500mm - 17.5" (5/15/99): fairly faint-moderately bright, fairly small, round, 0.8' diameter. Sharp concentration with a well-defined bright core and occasional stellar nucleus. I recorded a mag 14.5 star at the SE edge - but this appears to be a contact companion listed in the UGC notes as 0.3'x0.2' just 33" SSE of center! Forms a pair with NGC 5531 5.2' NNW.

600/800mm - 24" (6/15/15): moderately to fairly bright, moderately large, round, 0.8' diameter. Sharply concentrated with a bright core that increases to a very bright, quasi-stellar nucleus. Forms a close, physical pair with NGC 5532B = PGC 214240 just 34" S of center. At 375x it appeared faint to fairly faint, very small, 12"x8", contains a faint stellar nucleus. NGC 5531 lies 5.2' NNW.

Notes by Steve Gottlieb