Yes and yes , thanks. I picked up an Orion 2x shorty that works fine. M31 still looks the same. I need more photons in the tube. Or a bigger tube. Thanks for the wealth of info, I think I'm off to my next question.......
Why is glass or pyrex the chosen material for mirrors. It seems to me metal will be a lot easier and cheaper to remove minor spherical caps from flats within nanometer precision. Or a porcelain cast from the blank. ?..... Mirror treatment is all the same..... I am tempted to run a 4"x24" AlMg ingot thru my C&C machine then polish it up. Send it out for treatment. Done 23" mirror ?... Is there a reason why grinding glass is preferred, sounds exhausting.