The Dumbbell Nebula (also known as Apple Core Nebula, Messier 27, M 27, or NGC 6853) is a planetary nebula in the constellationVulpecula, at a distance of about 1,360 light years.
This object was the first planetary nebula to be discovered; by Charles Messier in 1764. At its brightness of visual magnitude 7.5 and its diameter of about 8 arcminutes, it is easily visible in binoculars, and a popular observing target in amateur telescopes.
The Dumbbell Nebula appears to be shaped like an 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 in the plane of the sky was no more than 2.3″ per century. From this, an upper limit to the age of 14,600 yr 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 some 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 photoionizationfronts.
Imaging telescopes or lenses: Meade LX200 12″ GPS Pier mount
Imaging cameras: QSI 640 WSG-8
Mounts: Meade LX200 fork mount standard fork mount
Guiding telescopes or lenses: Borg 101ED/F6.4
Guiding cameras: SBIG STi-C
Focal reducers: Starizona SCT Corrector f/7.5
Software: Cyanogen Maxim DL5, Software Bisque TheSky
Filters: Astronomik Ha 12nm, Asronomik OIII , Astronomic SII 12nm
Accessories: Shoestring Astronomy FCUSB, Focuser JMI EVN-2
Dates: Oct. 1, 2014
Locations: Home Observatory
Integration: 2.8 hours
Avg. Moon age: 6.54 days
Avg. Moon phase: 41.10%
RA center: 299.901 degrees
DEC center: 22.708 degrees
Pixel scale: 0.722 arcsec/pixel
Orientation: -10.793 degrees
Field radius: 0.291 degrees
Autor: Ray G, 04.10.2014