Astrophotography by Keith B. Quattrocch

NGC 4535 
 Spiral Galaxy in Virgo
 LLRGB Image
 Published in Sky and Telescope Gallery: December 2009
 Copyright 2009
  Keith B Quattrocchi

Image Acquisition Information                      
 
 Telescope: 16" RCOS Richey Chretien Telescope (ion milled at f/9) 
Camera: SBIG STL-6303 M
Guiding: SBIG AOL,  Astrodon  MOAG AOG (SBIG 237 with Custom FLR to
expand the FOV)
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: May 8, 2008 - May 25, 2009                              
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 Information:  This image is a multi-layered modified LLRGB image of NGC 4535, a small (7.1 by 6 arc-min) face on spiral galaxy in Virgo.  Based on Cepheid variable information  NGC 4535 is estimated to be 54 million light years distant.  It has a large number of forground stars which "pepper" the image.  It has an apparent  magnitue of 9.8.  There are several interesting background faint galaxies, one of which (upper left) is irregular and colorful. 
Additional Comments:  This image is a modified LLRGB composite.  An LRGB image was obtained using CCDStack and optimized in Photoshop CS/3.  This was then layered against an optimized (in Photoshop) luminance image (6 hour subframe image) with the process repeated twice, once with a luminance image and once with a modified LRGB image (accentuating some of the prominant H-alpha regions).  This was then further processed in Photoshop CS/3 (such as highlight/shadows and selective high pass filtering).