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'Donut' diffraction ring
Hello!
And welcome to my first post! I've been reading threads on this forum for a while but it was only once I hit a snag that I thought I would join in.... how selfish of me!
Anyhow....
I've hit an issue that I've scoured the net for and have not found any solution. I have an image (attached) that shows multiple donuts along the Dec axis (also the RA axis but not as pronounced. The image is overexposed but it is also apparent when I median 50 or so well-exposed images together as well. (Easier to see in the overexposed though)
I am thinking it is an issue somewhere in the optics... either reflections off the side of the optical tube or reflections off the filter. It looks somewhat like a reflection of the lens and secondary mirror but I cannot be sure, and nobody on the net seems to have had this issue!
Has anybody here seen this before or could hazard a guess at what it is?
I have a 12" Meade LX200 Classic with an ST7 with custom scientific RGBC filters.
Thanks in advance and hello everybody!
Michael
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