[ATM] 40" mirror

[Jay Kirkland <jaykirk2@compusmart.ab.ca>]

    There were step-by-step instructions in an article in Telescope 
Making mag in the early 80s on making your own mirror blank, that you 
might want to seek out. I remember it sounded like a lot of work, tho 
not impossible. One thing: I have never heard any follow-ups as to the 
long-term sucess of such mirrors.
    A big worry: at 4" thick that's a lot of glass to cool down. I think 
they were trying to fuse lightweight cellular large mirrors in the TM 
article.
    Of course they tell customers their humungous scopes are easy to 
use. But my puny 20" f5.7 is a monster, especially in cold weather. It 
gets used far, far less than it should. Hence yet another re-build. A 
40", you're probably looking at something that should either be 
permanently located in an observatory or something built right onto an 
observing trailer. Also, Obsession no longer sells their biggest scope - 
I can't remember if it was a 30 or 36". Dave Kriege said it was 
physically just too much to engineer, so he stopped production after 
about 6 of them.
    One of our local RASC members was building a 40". I haven't heard a 
thing about him in over 3 years.
    Not to sound overly negative, tho: that would be one awesome scope. 
I think you'd have to be insane to try it, but if it weren't for insane 
things being tried,
think of how much of the great stuff in this world that would never have 
happened.
   
   

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