Astrophotography by Keith B. Quattrocchi

NGC 7479
Face On Barred Spiral Galaxy in Pegasus
L-RGB/RGB 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: October 23 -November 20, 2008                               
Time: 18x20 min ( 6 hours) each for each of L, R, G, B:
Total of 24 hours imaging time.                              
Processing:  CCD Stack and PhotoShop CS/3
 
Image Infornmation:  Multi-layered L-RGB/RGB image of NGC 7479 in Pegasus.  This is a relatively small (4' x 3.1 arc-min) face on SBc (conspicuous bar) galaxy.   The center is unusually bright, making it easy to "burn" the core when processing.   The galaxy  is about 105 million light years distant.  It is a Seyfert galaxy (producing bright emission lines of hydrogen, nitrogen, helium and oxygen), with a centrally located supermassive balck hole.   These emisison lines may be due the effects of an associated accretion disc at  the galaxies core, where the supermassive black hole is thought to exist.

Additional Comments:  The image is technically an L-RGB/RGB image.  It was first assebled as an RGB object in CCDStack (DDP used).   In order to bring out some of the faint details two RGB images were produced.  One was a standard RGB image and the other a highly processed (heavy use of the high pass filter) image.  The two RGB images were combined as a single layer in Photoshop CS/3 and blended using the 'normal' mode (favoring the standard image, using the heavily processed image just enough to bring out some of the hidden nebulosities on the arms and core details).  The new RGB layer and the luminance layer were assembled in Photoshop CS3 (normal mode).  Further data stretching, high pass filtering and background smoothing was performed with Adobe Photoshop CS/3.