Object Analysis

The Blinking Planetary (NGC 6826) is a planetary nebula in the constellation Cygnus. It is one of the most famous examples of an optical illusion in astronomy. When an observer looks directly at the central star, the surrounding nebula seems to disappear, only to reappear when the observer uses averted vision. This "blinking" effect is caused by the way the human eye perceives light and contrast.

The nebula is located approximately 2,000 light-years away. At its center is a very bright O-type star, which is one of the brightest central stars in any planetary nebula. This star is currently in the process of becoming a white dwarf and is flooding the surrounding gas with ultraviolet radiation, causing it to glow with a distinctive green hue from ionized oxygen.

High-resolution images reveal two bright "fliers" or FLIERs (Fast Low-Ionization Emission Regions) on either side of the nebula. These are relatively young jets of gas moving outward at supersonic speeds. The nebula also features a faint outer halo, which represents the very first layers of gas the star shed thousands of years before the main nebula formed.