Re: [ATM] ritchey cretians

["Mitchell R" <funnybone101@embarqmail.com>]

-----Original Message-----
From: Lawrence D. Lopez [mailto:lopez@mv.mv.com] 
Sent: Sunday, January 20, 2008 11:19 AM
To: Mitchell R
Cc: atm@atmlist.net
Subject: Re: [ATM] ritchey cretians

Mitchell:

    It's an observation, not an ambition.

    It has been observed that many mechanical mirror making
    mechanisms turn out terrible mirrors because they are systematic.

    This doesn't mean that it can't be done or that it hasn't been done.

    By the same token humans systematically grinding mirrors have the
    same problems.

    It's only by introducing randomness in the right way that
    you get a perfect surface.

    It isn't magic.

    You are trying to get two surfaces to meet at any orientation.
    The only surfaces that do that are planes and spheres.
    Everything else is worn down.
    To meet the any orientation requirement you need to randomly
    grind in all orientations.

    This is very very basic mirror making.
   
Larry


Indeed. The original post wasn't by me but someone else. Excellent
explanation.

Clear Skies!

Mitch

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