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Monday, December 17, 2012

Messier 27, the Dumbbell Nebula

I reprocessed this image since weather doesn't support imaging up here and my processing work flow is somehow different now. My new work flow produces softer images with high details.

Messier 27, the "Dumbbell Nebula"

Ra 19h 59m 36.340s Dec +22° 43′ 16.09″

M27 in mapped colors, from the emission of ionized elements,
R=Sulfur, G=Hydrogen and B=Oxygen.
Click for a large image.

The Dumbbell Nebula (also known as a Messier 27, M 27, or NGC 6853) is a planetary nebula in the constellation Vulpecula, at a distance of about 1360 light years. It has a large angular diameter as a planetary nebula, about 8 x 5,6 arc minutes. (Rarely imaged outer halo is not included, it can be seen in my image. With an outer shell, the diameter is over 15'' (more than a size of the half a Moon)

Planetary nebulae are shells of gas shed by stars late in their life cycles after using up all of their nuclear fuel. The star then ejects a gaseous shell, which is illuminated by its extremely hot central star, a core left from the original star. n this image, the central star is clearly visible at very center of the nebula. 
M27's central star has a magnitude of 13.5 and is an extremely hot blueish dwarf with a temperature of about 85,000 K. Our own star, the Sun, is expected to undergo the same process in a couple of billion years.

A closeup from the image center,
the central star shines at magnitude 13,5

M27 in visual colors

Natural color composition from the emission of ionized elements, R=80%Hydrogen+20%Sulfur, G=100%Oxygen and B=85%Oxygen+15%Hydrogen to compensate otherwise missing H-beta emission. This composition is very close to a visual spectrum.
Click for a large image.


A mapped color closeup with a different orientation.

Technical details:

Processing work flow:
Image acquisition, MaxiDL v5.07.
Stacked and calibrated in CCDStack.
Deconvolution with a CCDSharp, 30 iterations.
Levels, curves and color combine in PS CS3.

Telescope, Meade LX200 GPS 12" @ f5
Camera, QHY9 Guiding, SXV-AO @ 6,5Hz
Image Scale, 0,75 arcseconds/pixel
Exposures H-alpha 14x1200s, binned 1x1
2 x S-II 1x600s, binned 3x3
6 x O-III 1x600s, binned 2x2

A single 20 min. H-alpha light frame
Calibrated with Bias corrected flat and Dark masters in CCDStack

1200 seconds of light from the ionized Hydrogen with Meade LX200 12" @ f5, Baader 7nm H-a filter and a cooled astrocam QHY9. Image is scale down ~50% from the original.
At the time of imaging, the seeing was kind of good, FWHM around 2,5.

Original version, from 2009, of Messier 27 can be seen here

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