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Old 09-01-2016, 02:57 PM
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RickS (Rick)
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Quote:
Originally Posted by raymo View Post
If one stacked a large number [ say 50, 75, or a hundred or more] of very short subs [say 8 secs] of M42 in order to retain the core of the nebula, what would happen if one added a single long sub that reveals more of the nebulosity and obviously blows out the core, and would the result vary according to how many very short subs were used? In other words, would the effect of the one long sub be diluted? Also, would the extra nebulosity shown by the long sub be diluted as well?
raymo
What happens will depend on your stacking software and how it normalises and weights the subs, but it won't be what you want

You need to stack your short subs and long subs separately then combine them afterwards. As Glen said, the "traditional" way to do that is with layers in Photoshop. Another option is to use HDR techniques to combine the short and long stacks and then compress the dynamic range back down to something you can represent on a screen or print.

Cheers,
Rick.
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