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Artifacts around bright star - what could it be?
Hi All,
Does anyone know what these dark doughnuts are that seem scattered around the star (Canopus) in this image? They only appear on the very brightest stars. They also seem to radiate from the star.
They don't look like regular dust artifacts, and collimation and focus is perfect. Could it be something to do with CCD microlenses??
I have opened the camera and found no dust apart from a few regular grains that I already see on my flats as the usual big doughnuts, nothing like this.
The image is a 20s exposure through my Luminance filter. I haven't had a chance to check through other filters yet.
Any ideas?
Regards,
Rolf
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