M27 (Dumbbell Nebula)

All Images Copyright Steve Cannistra

Please click here or on image for a larger size.
Please click here for this image in Ha light.
Please click here for this image in OIII light.
Please click here for an inverted version of this image.
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Magnitude:  about 7.3
Size: about 8'
Distance: 1,250 light years
RA: 19h 59m 36s
Dec: 22 degrees 43' 15"

This is a total 6 hour exposure over 2 nights (3 hours each for Ha and OIII).  The faint Ha skirt was easily detected (click here for Ha image, and here for the inverted image), due to the relatively long exposure and the high Ha sensitivity of the CM10 camera.  This camera has the Kodak KAF3200 microlensed chip and was ordered without the coverglass (QE curve shown here; original source document available here).  Although I did not realize it at the time, there is a faint OIII signal emitted from the skirt as well (click here for OIII image), making the color of this peripheral region more maroon or slightly magenta, as opposed to pure red.  It is also apparent that this peripheral skirt is not homogeneous, but rather ruffled and scalloped in nature, suggestive of jet-like emission as opposed to a slowly expanding outward bubble.  I am not certain about this and have submitted this question to others for advice.

Messier 27, also known as the Dumbbell Nebula, was the 27th object categorized by Messier during his search for objects that could be confused for comets.  M27 is a planetary nebula, which represents the end stage of stars about the same size as our Sun (in contrast, stars much larger than our Sun typically undergo a supernova explosion).   Such stars experience a phase of continued helium burning on their surface, long after the fuel in their core has been exhausted.  The outer layer is shed into space, igniting surrounding elements such as hydrogen through excitation by the solar wind and heat.  The term "planetary" nebula is a misnomer and was coined by Herschel, based upon its superficial visual resemblance to his recently discovered planet, Uranus.  More information about M27 may be found here.

Photographic Details:

Date:  July 1 and July 2, 2006.
Takahashi FS-102 at f6 , on the G11 Losmandy Mount.
Autoguider:  SBIG STV with e-finder.
Camera:  Maxcam CM10
Astronomik Ha (6 nm) and OIII (13 nm) filters.
Exposures:  Ha(Ha:OIII:OIII).  18 x 10' Ha (7/1/06); 18 x 10' OIII (7/2/06).  Total exposure time 6 hours.
Conditions:  Temperature 75 degrees F; intermittent thin clouds invading the area on both nights.
Debloomed, calibrated, aligned in Maxim.  Combined using RC Sigma Reject MaximDL, followed by DDP in ImagesPlus (IP).  Subsequent processing in Photoshop CS (16 bit format).  The color image was constructed as Ha:OIII:OIII.  The luminance was provided by the Ha image in order to enhance detail in the core region Ha(Ha:OIII:OIII).

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