Blinking Planetary

The Blinking Planetary (NGC 6826) is a planetary nebula in Cygnus, about 2,200 light-years away. It gets its name from a remarkable visual effect: when you stare directly at it, the bright central star dominates and the nebula seems to vanish, but with averted vision the nebula reappears.

Easy to find in Cygnus. In a 4-inch telescope at medium power, try alternating between direct and averted vision to see the "blinking" effect. The nebula is about 25 arcseconds across with a bright central star. Best in summer and autumn.

Discovered by William Herschel on September 6, 1793. The blinking effect was noted by observers and gives this planetary nebula one of the most descriptive common names in astronomy.