Cocoon Nebula (IC 5146)

Cocoon Nebula
All Images Copyright Steve Cannistra

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FOV 19 x 28'
Magnitude:  7.2
Distance: 4,000 light years
RA (J2000): 21h 53m 29s
(J2000): 47 degrees 16' 01"
Position Angle:  Minus 18 degrees (Pinpoint)

This is the second light image for my newly modified VC200L, which now includes thinner vanes and a outer edge mirror mask to correct a turned down edge.  The Cocoon Nebula floats like an island within a sea of dark clouds.  It is a star forming region that contains three of the major types of nebulosities:  emission, reflection, and absorption.    These three types of gas clouds are responsible for the red, blue, and black regions shown above.  The large central star within the Cocoon has blown a hole in the nebula and is likely responsible for exciting the surrounding hydrogen to emit in Ha light.  Please click here for more information about this object.

Photographic Details:

Date:  August 25, 26, 27, 2008
Scope:  Vixen VC200L at f9 (FL = 1800 mm) on the Takahashi NJP Mount.
Autoguider:  SBIG ST-402 with 60mm guidescope, focal length 227mm
Camera:  Apogee U32 -20C.
Astronomik Clear (unblocked), R, G, B filters.
Exposures (all unbinned):  Luminance: 42 x 5' = 210'; R: 8 x 10' = 80'; G: 8 x 10' = 80'; B: 10 x 15' = 150'.  Total exposure 8.7 hours.
Conditions:  Clear with FWHM in the range of 2.6 to 2.9".
Post-processing:  Debloomed, calibrated, aligned, and Sigma Clip combined in Maxim.  DDP in ImagesPlus (IP).  Deconvolution in Maxim using Bob Vanderbei's Fat Tail Deconvolution script (3 iterations).  Further processing in Photoshop CS (16 bit format).

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