GIMP and processing astrophotographs
The main idea is to use levels to expand the histogram and "bring out" the features hidden in the almost black. One way is to use Colors:Levels and move the center pointer to the right edge of the histogram, save and reopen moving the left pointer to the left edge of the histogram. Repeat until you see the hidden features (this has the effect of expanding the histogram and moving it toward the middle of the intensity graph.
An alternate and easier way is to us Colors:Levels:All Colors: Auto Input Levels
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| Original Image of Alnitak with hidden NGC2024 and IC434 |
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| After processing with GIMP: Colors: Levels: All Colors Auto Input Levels |
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| After cropping. Auto Input Levels works magic to bring how hidden features |
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| NGC2244:Rosette Nebula stacked |
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| Single Frame NCG2244 with aircraft flyby |
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| Rosette Nebula annotated by Astrometry.net |
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| Astrometry.net annotation close |
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| M31 uncropped |
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| M31 cropped |
