Re: ATM SDI Mirror

[Nick Martin <bonnyton@ednet.co.uk>]

At 04:31 PM 7/24/99 -0400, you wrote:
>Greetings all:
>
>In reponse to the discussion about ultra-thin mirrors, I thought I would put
>in my 2 cents. When I was a student at the University of Houston, one of the
>ME professoes there was working on a partial vaccuum parobolic mirror, made
>from a proprietary, mylar like material.  Essentially, he machined a rigid,
>short section of aluminum tube with a radius of about 18 inches. He mounted
>this mylar-like material on the top edge using a combination of adhesive and
>compression rings. The bottom was sealed with an aluminum plate welded in
>place. By drawing a partial vaccuum on the aluminum tube, the film depressed
>very nicely into a theoretically perfect parabola. I remember there was some
>very slight wrinkling around the edges, but this could have ben easily
>masked off yielding a mirror about 34 inches in diamter that wieighed
>perhaps 15 pounds, mirror and cell all together, pretty chep too.   Once
>beyond the wrinkled edge the mylar was utterly smooth.  I am certain this
>device was created as part of SDI, it sure did a great job of concentrating
>sunlight. The appearance of this thing was very beautiful, and my intuition
>tells me its optical characteristics were quite good, although I did not
>measure it.  I have always wondered why I haven't seen something like this
>elsewhere. It just has a nice elegance to it.
>
>FWIW (For what it's worth), VL
>
>
>Victor E. Lange

 A few years ago a team at one of the Scottish Universities developed
somewhat similar vacuum formed mirrors. It was reported in the press here.
With the usual level of foresight and initiative that marks the British
commercial attitude to innovation no development money was available here so
the whole project went over to the the USA. I've heard nothing more of it since.
Nick
Nick Martin, Bonnyton House, By Ayr, Ayrshire KA6 7EW ,Scotland, UK.
 Latitude 55 24'56" Longtitude 4 26' 00".
"Eppur si muove" Galileo Galilei