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Do you dither?
Howdy all
Id like to ask, do you dither, that is move the scope or lens slightly after taking each exposure of a stack? I did, then tried not dithering, just taking sucessive shots without moving the scope, and sure enough, I get more noise by not dithering, I guess each pixel responds slightly differently, and dark subtraction is never 100% accurate, so dithering can help smooth over non random noise.
I think dithering might be especially important for narrowband imaging as only certain colour pixels (eg red for Ha imaging) will be illuminated, the rest will be dark, so moving the camera/scope at least a few pixels each time will, when the images are aligned and stacked, help smooth out the pixels, at least thats the theory anyway.
For fast lenses and shorter exposures perhaps dithering is not necessary.
Scott
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