Astrophotography by Keith B. Quattrocchi


Soap Bubble Nebula
Faint Bubble Nebula in Cygnus
Composite Image: NB and LRGB Image
Joint Project by Keith B Quattrocchi and Mel Helm

Published:  Sky and Telescope Gallery:    December 2008

Copyright 2008
Keith B Quattrocchi

Please Note:  This object was first imaged and submitted to the IAU by Dave Jurasevich, several days before it was first noted and reported by Dr. Mel Helm (see below)

Image Acquisition Information                      
 
Telescope: 16" RCOS Ritchey Chretien Telescope (ion milled at f/9) 
Camera: SBIG STL-6303 M
Guiding: SBIG AOL, Astrodon  MOAG AOG (SBIG 237 with FLR)
Filters: Astrodon Ha, SII, OIII, L, R, G, B
Mount: Software Bisque Paramount ME
Acquisition Programs:  The Sky,CCDAutopliot III, CCD Soft. 
Processing Programs: CCDStack, Maxim DL, Adobe Photoshop CS/3
Date: July 30-August 13, 2008                              
Time: 21 x20 min ( 7 hours) for each of Ha, SII, OIII, L, R, G, B
Total of 49 hours imaging time.                              
Processing:  CCD Stack and PhotoShop CS/3
 
 
Image Information:  As I noted on the previous pages, we believe this nebula to be 'co-discovered' (technically, pending formal declaration by the IAU, the object has been "imaged", but whether it has been discovered is an issue still pending), first by Dave Jurasevich (of the Mt Wilson Observatory) on July 6, 2008 and submitted by him to the IAU on July 10, 2008.  His images were not posted at the time of our independant "discovery" (July 17, 2008).  He deserves recognition as being the first to image and submit this object.  You can learn about Dave's excellent work at www.starimager.com and about his initial discovery of this nebula at http://tinyurl.com/5q4qnu . 
The significance of this image is that it is a composite of LRGB and NB information. The image contains a great deal of "data', literally containing 49 hours of data.  The central blue star is mote clearly visable and some of the grainy characteristics of the NB image are no longer present. 
 
Processing Information:  The significance of this image is that it is a composite image of a layered NB image with RGB abd Luminance data.  The NB image was first assembled in CCDStack using two methods.  1)  The first was a Hubble Palette image with nothing selected for the luminance channel.  This produced an image with greater color variation and relative star preservation.  The ratios of SII, Ha and OIII were adjusted so that the green Ha signal did not overwhelm the image. 2)  The second image was produced as noted above but also contained the Ha data under "Luminance".  This brought out the fine Ha detail, some of which was lost in bringing out the SII and OIII data in the first image (the same ratios were used). 
An RGB and Luminance image were then layered onto the NB image in Photoshop CS/3 ('normal' mode with varied 'opacity').    Finally the image was further processed in Photoshop CS/3 (curves and levels, shadows/highlights, and high pass filtering).