I agree with Steffen. "stretch" marks or stresses in glass can only be seen under polarized light on uncoated glass.
Quote:
Originally Posted by Steffen
I'd say that mirror has been poorly cleaned/dried after cleaning. Condensation from breathing or dew will show up those cleaning marks very clearly. It does not mean the mirror is defective or underperforming in any way. The only way to gauge its performance is a star test.
Celestron or their agent should have offered a professional clean at the least, though.
Cheers
Steffen.
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