Astrophotography by Keith B. Quattrocchi

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 Infornmation:  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).