Edward Pickering discovered NGC 6790 on 16 Jul 1882 using a direct-vision spectroscope with the 15-inch refractor at Harvard College Observatory. He noted "very bright and minute." The discovery was announced in AN 2454 and The Observatory, Vol 5, for Oct 1882.

Based on Crossley photographs at Lick, Curtis (1918) reported "Indistinguishable from a star on the Crossley negatives, but shown to have a minute disk visually with the 36-inch refractor."

300/350mm - 13" (7/85): bright, just non-stellar 220x, estimate mag 10, easy blinker with OIII. A mag 11 star is 30" W. Forms the east vertex of a thin rhombus of mag 10 stars.

400/500mm - 17.5" (7/28/92): at 82x, very bright, stellar, surprisingly prominent, estimate V = 10.0. Blinks well with an OIII filter. At 280x appears very bright and a very small but definite disc about 5" diameter is visible with a bluish color. A mag 11.5 star lies 35" W.

Notes by Steve Gottlieb