Dithering

Questions and answers about processing in StarTools and how to accomplish certain tasks.

Dithering

Postby Rkonrad » Wed Apr 25, 2018 12:17 am

For practical reasons, dithering my frames is nearly impossible. Though this is not startools related, I was wondering if I could achieve the same results by working on my light frames in pre-processing before stacking. Perhaps I could fix a moderate crop on an image and then randomly move the crop around each successive one. The crop size would of course have to be identical. Darktable allows me to apply the same crop to each frame. After that I would do the adjusting. Does this make any sense? Cheers. Richard
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Re: Dithering

Postby admin » Wed Apr 25, 2018 11:14 pm

Hi Richard,

That's not going to work unfortunately.
The whole idea behind dithering is that different + unrelated + non-colocated CCD wells/"pixels" get a chance to record the same detail.
Stacking then averages out the small biases the CCD wells/"pixels" have.

If it's entirely impossible to dither, then bias or dark frames should help mitigate the pattern noise as well, but dithering is much preferred.
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Re: Dithering

Postby Rkonrad » Thu Apr 26, 2018 3:16 pm

:(
I'm not able to guide so the only option would be babysit my mount and do it manually which is not possible. Maybe auto guiding could happen in the future. Thanks Ivo.

Richard
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Re: Dithering

Postby Rowland » Mon Apr 30, 2018 9:55 am

Hi Richard. What mount and camera do you have. For many years I ran a standalone intervalometer with integrated ditherng unguided _ It worked exceptionally well. I have the code and hardware specs if you are interested.
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Re: Dithering

Postby Rkonrad » Tue May 01, 2018 12:10 am

I'm using a canon 600d or t3i with a celestron avx mount. Im trying to learn how to use ekos from kstars which has a new function - unguided dithering. I haven' tried it yet but am somewhat wary. The AVX manual states to always end a slew with either the "up" key or "right" key -assuming this has something to do with backlash.

Sorry for the tangent - YES I would love to know all I can so Rowland please send me the information. Much appreciated.

Richard
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Re: Dithering

Postby Rowland » Thu May 03, 2018 11:17 am

Hi Richard.

PM on the way.
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