I think I've finally cracked the Newton's ring problem with the new ZWO ASI cam - simply defocus the image for a flat. :) The tilt adapter worked, but at short f. ratios it was beginning to cause differential focus. I had abandoned the defocus method with the DMK31 as the FOV was such that the area beyond the limb used to mess up the flats, but it's perfect for the ASI. : The sun was pretty low of course but I'm pleased with the results considering. Note the detached prominences and the countersunk appearance of the disappearing AR11899. :)
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And a coloured inversion. :)
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