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Odd arcs in test image
I wonder if anyone can help diagnose the source of the odd bright arcs visible at the top of the attached image?
It was taken with a GSO RC10CF and SGBIG ST2000xm. There was an AP CCDT67 FR in line and a FW fitted with Astronmik filters. I used DSS to calibrate and stack the images.
It does not look like reflections in the FR to me.
Could it be a result of field rotation (my polar alignemnt was not accurate) and processing (I did not do use flats but did use darks)? I do not see these issues in the subs even when pushed hard...
Any ideas?
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