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Advice on How to Process Stars

Processing Deep Sky Blooming
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Andre Vilhena avatar
Andre Vilhena avatar
Hello Everyone,

One of the things I most like to preserve is star colours. However, in the majority of the photos there are always some stars whose cores are burned, in a lesser or greater extent.
Which would be the best way to avoid star core saturation and keep its colours? I am thinking that maybe taking some subs with much smaller exposure time and blend the cores of these subs in the main subs. Does this make any sense? If yes, how could it be achieved in PI?

Thanks.
André
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Doug Summers avatar
Doug Summers avatar
Well, the primary issue of course is not to over saturate in the first place.  So, finding an optimal sub calculator (check CN or other on-line sources), and verifying against your setup is the best first strategy.   Afterwards, I like to use the color clip script during linear post-processing for those special saturated cases (not without some sacrifice in peak intensity at the star's very core).   Transition from linear to non-linear using masked stretch has worked better for me than the classic STF/HT method as it relates to retaining star colors.   Others may have good advice for pixel math blended solutions, but for the most part, I've found good fundamentals (starting with exposure calculators) go a long way.    CS  Doug
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Andre Vilhena avatar
Andre Vilhena avatar
Hi Doug,

Thanks a lot for your feedback. I usually have a look at Sharpcap exposure calculator but usually the recommended exposure is too small and I'd be ending up with hundreds of frames to process. But from your answer, I suppose that having a set of really small exposures to blend may make sense - "just" need to figure our the best process.
But still, I'll have a look into that script.

Andre