Astrophotography by Keith B. Quattrocch

NGC 4236
Spiral Galaxy in Draco
LLRGB Image 

Copyright 2008
Keith B Quattrocchi

Image Acquisition Information                      
 
Telescope: 16" RCOS Richey Chretien Telescope (ion milled at 6/9) 
Camera: SBIG STL-6303 M
Guiding: SBIG AOL, Astrodon  MOAG AOG (SBIG 237 with FLR)
Filters: Astrodon L, R, G, B
Mount: Software Bisque Paramount ME
Acquisition Programs: The Sky,CCDAutopliot III, CCD Soft. 
Processing Programs: CCDStack, Maxim DL, Photoshop
Date: June 27-July 4, 2008                               
Time: 15x20 min ( 5 hours) for each of L, R, G, B:
Total of 20 hours imaging time.                              
Processing:  CCD Stack and PhotoShop CS/3
 
Image Infornmation:  NGC 4236 is a face on barred spiral galaxy with  low surface brightness (about 24 mag/arc-sec²), located in Draco.  It appears to be a part of the M81 local group of  galaxies, although some references put it just outside of the M81 group.  In either case, it is about 11.7 million light years distant.  Because of it's low surface brightness (and I suspect its relatively amorphous blue color) there appear to be few images of this galaxy on amateur websites.  Being a bit closer than M81, yet much less bright, and may be obscurred to some degree.  The exact cause of this discrepancy in brightness is not known.   
 
Additional Comments:  The image was assembled in an LLRGB format  as a result of its relatively low surface brighness.  The initial LRGB image was assembled in CCDStack.  The LRGB image was layered into a Luminescent image in PS CS/3 (color layer option).  Further data stretching, high pass filtering and background smoothing was performed with Adobe Photoshop CS/3.