M27 Dumbbell Nebula, H-alpha enhanced
This image is a combination of an old Starshooter Pro OSC image and a more recent H alpha image acquired with the Parsec 8300M, both on the 120ED refractor. The processing was as follows: images aligned with Maxim; H alpha stretched with gamma=0.5; H alpha converted to natural colors using Carboni routine; blue portion of nebula selected, strongly feathered (4 pixels) and this area deleted from the H alpha to let blue come through; cyans in the OSC increased in saturation and Carboni routine 'Increase star colors' applied twice; layers composited using "lighten" in Photoshop; enhanced H alpha reapplied as a luminance screen; Carboni routines 'deep space noise reduction' and 'contrast enhancement' applied.
One can question the fairly saturated colors in this image. And although processing of astrophotos routinely far exceeds anything acceptable in most photography, I am slightly troubled by the need to delete part of the H alpha image to allow the blue portions of the nebula to show well. This sort of thing is often done when, e.g., bright areas of short exposure 14 bit SLR images are copied onto long exposure images to reduce 'blowouts'. But that is a workaround to shortcomings of the detector, not an actual deletion of data. So I call this image artistic, and not scientific.
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