Quote:
Originally Posted by gregbradley
My opinion is flats are more vital if you have any light pollution, use a scope with a smallish corrected circle, have dust issues with the chip or filters, or use a large chipped camera, use longer focal length or want to increase contrast in dim areas plus make the image look more balanced and even.
I see a definite improvement even with the 694 chip on my CDK17. The vignetting is mild to weak but its still there. If a dim part of say a galaxy falls in that zone it loses contrast. There is a gain, not massive and nothing like what is needed with the 16803 chip but still worth it.
Greg.
|
so you are just using flats to correct for illumination variability - not FPN? If you are not trying to reduce pixel-level fixed pattern noise, have you considered (or tried) noise filtering on the flats?