I am looking to build a mirror mount for 20x80 or 25x100 binoculars.
Something like this one.
http://www.tricomachine.com/skywindow/index.html
My question is; how do I establish what quality of mirror will be needed for This level of magnification.
I do not know how to calculate if I would need 4 wave, 1 wave or 1/4 wave and there is a LARGE price difference.
I am hoping someone has used one of known mirror quality, for a known magnification.
Or even better is someone knows how to calculate this.
Many Thanks