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The planetary nebula M27 in Vulpecula, also known as the Dumbell Nebula, set in a rich star field.

In 1762 Charles Messier discovered the 27th object in his catalogue, describing it as an oval nebula without stars. Later John Herschel gave it its common name, the Dumbell Nebula.  It was the first planetary nebula to be discovered and is the remnant of a giant star that exploded at the end of its life leaving a cloud of dust and gas surrounding the dying ember of its core a so called white dwarf star about the size of the Earth.  This white dwarf is still extremely hot, about 85,000K, and so is emitting ultraviolet light which is exciting the surrounding gas shell and making it glow. 

The nebula is 8 by 6 arc minutes in angular size and 7.4 in magnitude.  Its distance is not well known, perhaps 1,250 light years, and measurements of its rate of expansion, some 6.8 arc seconds per century, gives an estimated age of three to four thousand years.


Image info

Telescope:  Celestron 9.25" Schimdt-Cassegrain at f/6.3

Focus:  Prime focus

Filter:  Celestron LPR filter

Mount:  Vixen GPD with Skysensor2000

Camera:  Modified Canon EOS 300D, at ISO800

Guiding:  700mm refractor guidescope, SAC7 camera, autoguided with Guidedog software

Exposure:  Total 48 mins (16 x 180s)

Date:  28th May 2005

Processing:  RAW file conversion, Offset and Dark subtraction, flat fielding, registering and stacking done in IRIS. Colour enhancement using the 'asinh' function in IRIS.  IRIS pre-processing almost all automated with AutoIt scripts.  Curve stretching in Photoshop CS, noise reduction in Neat Image.




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