page 28 M16 NB

                       Astrophotography by Keith B. Quattrocchi

    M16 (NGC 6611) and IC 4703
    The Eagle Nebula in Serpens Cauda
    Narrow Band Image


                                      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 Ha, SII, OIII
                               Mount:        Software Bisque Paramount ME
                               Acquisition Programs:   The Sky,CCDAutopliot III, CCD Soft. 
                               Processing ProgramsCCDStack, Maxim DL, Photoshop
                               Date: July 5-July 24, 2008                              
                               Time: 18x20 min ( 6 hours) for each of Ha, SII, OIII
                               Total of 18 hours imaging time.                              
                               Processing:  CCD Stack and PhotoShop CS/3
Image Information:  The "Eagle Nebula", about 7,000 light years distant,  is made up of an open star cluster (technically known as M16, or NGC 6611) and an emission nebula (IC 4703, ie, "The Eagle Nebula").  These two are popularly known, together, as the "Eagle Nebula".   The nebulosity is a diffuse emission nebula in Serpens Cauda.  The Pillars of Creation are seen on the right and the "Spire" (which is some 9.5 light years tall)  to the left.  Both are H II regions responsible for the creation of new stars (about 5 million years old).  Young stars emitting ultraviolet light are presumably eroding both the spire and the pillars. 
Processing rocessing Information:  The 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 SII were adjusted so that the green Ha signal did not overwhelm the image, leaving it as a pure green image (ratios were:  20:1:36, with the dark nebulosity below the pillars of creation used for background, as there were no true background areas in my FOV).  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).  This can also be done in Photoshop alone, and a composite or luminance addition can be used to bring out further standard broad spectrum star and color data. 
  Finally the two images were separately processed in Photoshop CS/3 (curves and levels, shadows/highlights, high pass filtering) and blended in Photoshop CS/3. 

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