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Camera Comparison Before/After Modification: NGC7635



Object The Bubble Nebula (NGC7635), in Cassiopeia  (Open Cluster M52 near bottom) 
Telescope (Photo) Televue 85mm refractor @ f/5.6 on Losmandy G11 Mount
Telescope (Guiding) Celestron 8" SCT OTA @ f/10 on Losmandy G11 Mount
Camera (Photo) Canon 50D DSLR, before (top)and after (bottom) image sensor filter modification
Camera (Guiding) Meade DSI III w/PHD Guiding
Exposure Detail Before:  Uncropped, excluded-average combination of 19 images
After:  Uncropped,  excluded-average combination of 17 images
Both:  sub-images exposed at 300 seconds each, ISO3200;  RAW file conversion, full calibration (flat, dark, bias, and flat-dark), and initial image processing using ImagesPlus 3.80; final image processing using Photoshop CS3
Location Cincinnati Astronomical Society's Dark-Sky Site (Adams County, Ohio) (N38.876, W83.464)
Date Before:  08/15/09
After:  09/11/09
Comments These images in this sequence were taken through the same optics and mechanics prior to and after modification of the camera.  The modification consisted of removing the factory filter in front of the image sensor and replacing it with a custom filter for improved red sensitivity.  Both images were processed identically (the "after" image required color-balancing first) and are uncropped.