Ralph Copeland, LdR's assistant, discovered NGC 7766 along with 7767, on 9 Oct 1872 and labeled it Delta in the sketch. He measured a separation of 85" SSW from NGC 7768 and at this exact offset is CGCG 477-018 = PGC 72611.

400/500mm - 17.5" (7/20/90): extremely faint, very small, round, low even surface brightness, requires averted vision. A mag 14.5 star is 45" WSW of center. Located 1.4' SSW of NGC 7768 and 2.3' N of NGC 7767 in the core of AGC 2666. Extremely faint NGC 7765 lies 2.5' NNW.

600/800mm - 24" (8/5/13): very faint to faint, thin edge-on 3:1 SW-NE, 20"x6". Situated just 1.4' SSW of NGC 7762. A mag 13 star lies 1.2' NE and a mag 14.5 star is just 0.8' WSW.

Notes by Steve Gottlieb