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Old 15-08-2011, 01:25 AM
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Grahame (Grahame)
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Favourite data rejection method

Just going to throw it out there - what does everyone use for data rejection methods in which ever flavor of software your using to stack images?

I find myself using the sigma reject method most of the time in CCD Stack, with occasional use of clip min/max also.
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Old 15-08-2011, 09:56 AM
jase (Jason)
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CCDStack

I use Poisson sigma-reject on small stacks (4 to 8 subs). Its very reliable at detecting outliers after good normalisation (selecting both background and highlight manually).

For large stacks (8+ subs), STD sigma-reject is preferred. Poisson can still be used however but I've found that you don't need a strong standard deviation value.

If the data is of good quality a deviation value of 2.2 works well. I'll drop down to 2 or 1.8 for mediocre. For a small stack of RGB, at times I'll drop down to 1.5 deviations. I rarely go lower than this.

Hope that helps.

Cheers
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Old 17-08-2011, 11:27 AM
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tlgerdes (Trevor)
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Favourite Data Rejection method: Telling Fred V he is full of it and moving on
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Old 17-08-2011, 12:18 PM
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lol!

H
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Old 17-08-2011, 12:47 PM
jase (Jason)
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You may be in for a surprise. With poor data normalisation, Fred V may not be computed as an outlier thus not rejected. As a result Fred would be embedded to increase 'signal over noise'. Put another way, he may be full of it, but his parted wisdom is 'gold over crap'.
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Old 21-08-2011, 03:37 PM
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Poisson for Small stack, STD sigma reject for large ones. I aim at getting between 1 and 2% rejection on most of the frames.
Geoff
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Old 21-08-2011, 08:23 PM
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Thanks everyone, general consensus seems to be heading the same way - I have been using roughly the same percent rejection however always used poisson reject for all my stack rejection.

Grahame.
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