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Re: [ATM] correction -+

    Yes. Originally it was simply to participate and learn. I intend to experiment with larger glass purely for experiance, but i also want to try one pyrex mirror for purist sake.
    I've discovered a universe because of what you guys have put together and a faith in human co-operation. So, it's not entirely the ideal that's important, not in an imperfect world. However, i do appreciate the truth of what you proclaim. i may even understand optics befor it's too late. One motive for this hobby is to keep or try to keep the brain going. It's a steep slope after 60 - no?
Thanks Ken
                Ken 
    
  ----- Original Message ----- 
  From: Ken Hunter 
  To: KR ; atm@atmlist.net 
  Sent: Saturday, June 23, 2007 7:26 PM
  Subject: Re: [ATM] correction -+


  You asked, so...

  Plate glass behaves this way. Bad plate glass behaves worse than good plate glass. Problem is, plate glass is not made for telescopes so you never know until you are done if you have the good or bad variety. This has caused many folks to search for better glass and even to make glass specifically for telescope mirrors... imagine that.

  I have always tried steering folks away from plate glass and towards PYREX or better glass. Lately those efforts have been poo-poo'd and I've pretty much stopped giving advice. 

  My thoughts on the matter are: If you are going to take a raw material and spend hundreds of hours trying to make it as perfect as possible, subject it to widely variable temperature extremes and expect it to behave properly, why not start out with a material that can match your expectations?

  The primary mirror is the defining component in any telescope... Why limit your chances with a poor choice of materials from the beginning? The difference in price looks pretty trivial about now - no?

  Ken Hunter

  KR <kreid@primus.ca> wrote:

    Star test will tell in the end. Does anyone have thoughts on this?
    Thanks KMR 



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