[OzEclipse (Joe Cali)]

Originally Posted by Windshift

I wonder if this type of mirror would be of adequate quality for 25 times magnification ??

http://www.edmundoptics.com.au/optic...mirrors/32248/

it is 4-6 wave and enhanced aluminum coated

A good quality refractor objective is capable of up to 50x magnification per inch of aperture. 25x100 binoculars are of lower quality and are working at about 1/10th of that. You'll be looking at an angle much of the time so you need to at lease double the wavefront error. Maybe something better than this but you definitely don't need a 1/4 wave mirror.

If you want to get an idea on the cheap, try a piece of new dark tinted plate glass on the moon Jupiter or Sirius. Get one side sand blasted or grind it yourself then spray paint the sandblasted side with black paint. View them at different magnifications.

Joe