NGC 6826

NGC 6826 (also known as Caldwell 15) is a planetary nebula located in the constellation Cygnus. It is commonly referred to as the "Blinking Planetary", although many other nebulae exhibit such "blinking". When viewed through a small telescope, the brightness of the central star overwhelms the eye when viewed directly, obscuring the surrounding nebula. However, it can be viewed well using averted vision, which causes it to "blink" in and out of view as the observer's eye wanders.

NGC 6826

Emission nebula
Planetary nebula
Hubble Space Telescope (HST) image of NGC 6826 Credit: HST/NASA/ESA.
Observation data: J2000 epoch
Right ascension	19h 44m 48.2s[1]
Declination	+50° 31′ 30.3″[1]
Distance	~2000 ly
Apparent magnitude (V)	8.8[2]
Apparent dimensions (V)	27″ × 24″[2]
Constellation	Cygnus
Physical characteristics
Radius	0.22 x 0.20[2] ly
Designations	HD 186924, SAO 31951,[1] Caldwell 15
See also: Lists of nebulae

A distinctive feature of this nebula are the two bright patches on either side, which are known as Fast Low-Ionization Emission Regions, or FLIERS. They appear to be relatively young, moving outwards at supersonic speeds.^[3]

HD 186924 is the central star of the planetary nebula. It is an O-type star with a spectral type of O6fp.^[1]

See also

• List of NGC objects
• Planetary nebulae