NGC 6826 (also known as
Caldwell
Caldwell may refer to:
People
* Caldwell (surname)
* Caldwell (given name)
* Caldwell First Nation, a federally recognized Indian band in southern Ontario, Canada
Places
Great Britain
* Caldwell, Derbyshire, a hamlet
* Caldwell, East ...
15) is a
planetary nebula located in the
constellation
A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object.
The origins of the e ...
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.
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.
The central star of the planetary nebula is an
O-type star with a
spectral type of O6fp.
[
]
Gallery
File:NGC_6826_"Blinking_Eye".jpg
See also
* List of NGC objects
* Planetary nebulae
References
External links
*
*
{{Cygnus (constellation)
Cygnus (constellation)
Planetary nebulae
6826
015b
015B () is a South Korean music duo that debuted in 1990 and went on to become one of the country's most popular acts of the early 1990s. The group name which means literally "A crow flies across the sky" and it consists of brothers Jeong Seok-won ...