Truman Safford discovered NGC 6099 = Sf 76 = Sw. VI-89, along with NGC 6098, on 24 Apr 1867. In his 1887 list (too late to be included in the main NGC table) Safford described a "double nebula, pretty faint, dist 40"." His position is off the southeast side of this close pair. Lewis Swift found the pair again on 3 Apr 1887 and reported it as the 89th object in his 6th discovery list: "eF; vS; R; forms D neb with above." Swift is credited with the discovery in the NGC.

400/500mm - 17.5" faint, very small, slightly elongated NW-SE, stellar nucleus. Forms a very close double system with similar NGC 6098 off the NW edge and just 36" separation!

600/800mm - 24" (7/20/17): at 375x; moderately bright, fairly small, roundish, ~30" diameter, sharply concentrated with a small very bright core, high surface brightness. NGC 6099 and 6098 form a contact pair of ellipticals with the companion just 36" NW between centers. Situated 10' SW of mag 7.8 HD 146588.

Notes by Steve Gottlieb