Quote:
Originally Posted by Slawomir
Rick - I understand that only stacking of 2 master subs have been compared here. If that's the case, then I am almost certain that also registering individual subs with PI star alignment with distortion correction would yield even better result.
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I think all the packages would probably produce better results registering individual subs but it's a tricky problem and simple transformation, rotation and scaling isn't enough to do a good registration in this case.
Quote:
Originally Posted by LewisM
I foun d similar results as you know - I had an issue with CCDStack and PI wanting to only register the hot and cold pixels and ignore the stars - the big issue for me is, because I use OSC and MUST debayer peior to registration, of course the algorithms are going to like saturated colour pixels more than white.
Anyway, I found a way in CCDStack to now get a result as TIGHT as PI, and in far less time. I had to register and then register the lanzcos/sinc36 twice in CCDStack until there was NO discernable image shift on blink.
PI did the same in the end for me too, but the process takes a LOT longer for the same end result (there is NO star size difference in the end when you overlay each stack on each other).
So, I am still undecided if to use PI or CCDStack despite my PI victory last week 
PI REALLY needs to get more friendly with their output scripts too - they need to have an EASILY found "Save Scaled Data" function, not squirreled away in technospeak . PS REAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAALY hates PI's TIFFS - the level histogram is impossible to work with |
If you want to compare star sizes use the FWHMEccentricity script. It will do a much better job of figuring out FWHM than you'll ever do by eye. It will also show how the FWHM varies over the FOV.
I'm sure I've written 32-bit TIFF files that were OK in PS. Don't remember offhand what options I used, though.
Cheers,
Rick.