Re: [ATM] Subject: light weight mirrors--mylar!

[fundo@bellsouth.net]

We had a discussion several years ago on the list about plastics.  One of the problems is that they absorb more water that most folks realize.  

There is the possibility that Mylar or some polymer could be molded with a varying thickness that would produce a parabola when flexed either mechanically or via air pressure reduction.  I believe that Peter Chen was looking into something along this line at some point.  The problem, as always, is getting a suitable optical surface to aluminize.  I think we already have the technical ability to make continuous adjustments due to varying temperature and air pressure through an observing session.

*****-----
Dan F.
Memphis, TN
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