William Herschel discovered NGC 6255 = H III-689 = h1973 on 16 May 1787 (sweep 739) and recorded "eF, cL, iE nearly in the parallel." JH made the single observation "eF; vL; E in parallel; 2' l, 1' br." On 6 May 1850, LdR (or observing assistant George Stoney) noted "Query is it a double streak with a nucleus or a * at f end." The "star" at the following end is an HII complex seen in my observation.

400/500mm - 17.5" (7/1/89): very faint, moderately large, very diffuse, low even surface brightness, elongated 5:2 E-W. A mag 14 star is off the south edge 1.8' from the center.

600/800mm - 24" (6/12/15): at 375x; fairly faint, moderately large, very elongated 3:1 E-W, 1.5'x0.6', low but uneven surface brightness. At the east end of the galaxy is either a blue dwarf companion (HS 1653+3634) or more likely an intensely active star forming complex. At 375x a very small, nearly stellar knot was visible just off the east end of the main glow. The knot had a higher surface brightness than the main galaxy.

Notes by Steve Gottlieb