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    Re: CN aboard a Cessna 172
    From: James N Wilson
    Date: 2010 Feb 1, 14:15 -0800

    Personal experiences with large telescopes.
    
    The title of this post is wrong, but the talk about Palomar being the
    perfect machine prompts this reply.
    
    As a youth, I visited Palomar shortly after the mirror had been first
    tried. Its surface had to be changed from parabolic to hyperbolic, and
    that process was going on then. I could actually "kick the tires" of the
    mirror. Normally, visitors were not allowed in the room, since their body
    heat would upset the balance.
    
    More recently, our travel agent specializes in astronomy vacations, and
    he found that he could rent the Mount Wilson telescopes for a quite
    reasonable price. We first used the sixty inch one, the first ever large
    telescope, to look at Mars and other objects. Later, he rented the 100
    inch one, and we looked at Mars at its closest approach in 60,000 years.
    They had a Mickey Mouse viewing setup, but we could actually look through
    the telescope. We were told that the mirror was superior to the Palomar
    one, because it had been figured to near perfection. The Palomar one was
    figured only to the precision then needed. But with modern electronic
    enhancements, the 100 inch one is better. The construction of these
    telescopes was quite a feat, since nothing like that had ever been done
    before. That the 100 inch telescope looks like a battleship is because
    the only contractor who could build something that large was a
    shipbuilder. The telescope is floated in Mercury to take the load off the
    bearings.
    
    Fascinating.
    
    Jim Wilson
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