Quote:
Originally Posted by philiphart
That's a high quality image Bert.. star colours also looking natural which is not always easy with widefield imaging.. often end up with halos that discolour the image. very nice work indeed. would look good in a huge frame :-)
Phil
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Sorry Phil I must have missed your post.
There are a few things working in my favour.
Optics the best available a this focal length. I have baffled the lens by exterior aperture at f/3.6 and extended lens hood so there is no scatter inside the lens of light that does not contribute to the image. The lens only 'sees' the bit of sky it is imaging.
I now use an 82mm Hutech filter accurately mounted in front of the lens. This further contributes to contrast enhancement as no light due to light pollution that is not forming the image enters the lens.
As for haloes. I dither at about the 25 pixel level between exposures. When the upsized images X1.6 are stacked it minimises 'bleeding' of star colour into darker pixels next to bright stars. this also has the effect of improving resolution. They are the same thing.
The real control I have is my HDR method. When adjusting contrast, levels, stretching and saturation I am drawing on six 190MB images with exposures from 7s to 240s at the same time! The trick was to work out what the starting images should have done to them.
I may write a full 'how to' but at the moment it is still in development.
I will answer any questions though.
Bert