Quote:
Originally Posted by rustigsmed
hi bo,
you will need to have the camera aligned as it was when attached to the scope.
I hope you don't mind, i've done a synthetic flat and subtracted it from the pic.
this can be done on globs and galaxies usually and is muh harder on nebula as its hard to know where the gradient is exactly. so definitely look into flat acquisition - it is way better. it improves images more than any other calibration technique as far as i'm concerned.
2 copies opened in PS, one copy dust and scratches to fuzz out stars.
clone tool used to guestimate what the gradient would be doing over the bright glob area.
apply gaussian blur to smooth out clone tool hard edges (over entire image).
go to the original pic, go to apply image (then select the blurred image to apply), then choose subtract mode (offset around 15-20 and i used 100% subraction).
have attached the resultant version and the artificial flat. (it often does weird things at the edges unfortunately).
cheers
rusty
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Hi Rusty, that sounds like a really interesting technique . Can you outline the exact steps, I am having trouble trying to do it and I would love to give it a go
Thanks