The Dumbbell Nebula (also known as the Apple Core Nebula, Messier 27, and NGC 6853) is a planetary nebula (nebulosity surrounding a large star) in the constellation Vulpecula, at a distance of about 1360 light-years. It was the first such nebula to be discovered, by Charles Messier in 1764. At its brightness of visual magnitude 7.5 and diameter of about 8 arcminutes, it is easily visible in binoculars and is a popular observing target in amateur telescopes. The Dumbbell Nebula appears shaped like a prolate spheroid and is viewed from our perspective along the plane of its equator. In 1992, Moreno-Corral et al. computed that its rate of expansion angularly was, viewed from our distance, no more than 2.3 arcseconds (″) per century. From this, an upper limit to the age of 14,600 years may be determined. In 1970, Bohuski, Smith, and Weedman found an expansion velocity of 31 km/s. Given its semi-minor axis radius of 1.01 ly, this implies that the kinematic age of the nebula is 9,800 years. Like many nearby planetary nebulae, the Dumbbell contains knots. Its central region is marked by a pattern of dark and bright cusped knots and their associated dark tails (see picture). The knots vary in appearance from symmetric objects with tails to rather irregular tail-less objects. Similarly to the Helix Nebula and the Eskimo Nebula, the heads of the knots have bright cusps which are local photoionization fronts.

Telescope: ASA N16 f3.6
Mount: Astro Physics 3600GTO “El Capitan”
Camera: SBIG STL-11000M
Guider: SBIG STL-Internal

L: 48×10 mins = 480 mins, R: 12×10 mins = 120 mins, G: 12×10 mins = 120 mins, B: 12×10 mins = 120 mins

Total Imaging Time: 11h 10m

Data Imaged remotely over 5 nights during September 2012.
Data acquisition & Processing by David Churchill.

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