Heinrich d'Arrest discovered NGC 6307, along with NGC 6310, on 27 Oct 1861 with the 11-inch refractor at Copenhagen (first night he made discoveries with this telescope). He noted the mag 13 star at the north end (measured at 20") and his position is accurate.

400/500mm - 17.5" (6/18/88): fairly faint, small, elongated NNW-SSE, bright core. A mag 13.5 star is at the north end 0.5' from center. Forms a close pair with NGC 6306 1.4' SW.

Notes by Steve Gottlieb