Characteristics:
Magnitude:  7.2
Size: about 12'
Distance: 4,000 light years
RA: 21h 53m 24s
Dec: 47 degrees 16' 00"

Description:
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. 

Photographic Details:
Date:  September 5, 2004
Scope:  Takahashi Sky 90 at f4.5 with field flattener/focal reducer, on the G11 Losmandy Mount.
Autoguider:  SBIG STV with e-finder.
Camera:  SXV-H9
Filter:  Astronomik Ha filter (13 nm bandpass); Type II R, G, B filter set.
Exposures:  Ha:(HaR:G:B).  20 x 5' for Ha; 6 x 5' for B; 4 x 5' for R and G, all unbinned.  Total exposure 170 minutes.
Conditions:  Temperature 52 degrees F; above average transparency; above average seeing; calm; moonlight during Ha imaging.
Post-processing:  No darks, flats, or bias frames used.  Alignment done in ImagesPlus.  Sigma combined using RC Sigma Reject Plug-in for MaximDL.  DDP was performed in ImagesPlus (IP).  Subsequent levels and curves adjustments in Photoshop CS (16 bit format).