[ATM] Subject: light weight mirrors

["Richard Schwartz" <richard1941@gmail.com>]

If you really want a thin mirror challenge, why not make the mirror out of
1/4" plate glass, or better yet, saran wrap?    If you work the flotation
cell right, you might not have to grind or polish anything; just bend the
mirror to the correct shape!

If you think I am kidding, I have actually done this.   But it was a solar
cooker, not a telescope.

. . . Richard


-----Original Message-----
From: atm-bounces@atmlist.net [mailto:atm-bounces@atmlist.net] On Behalf Of
horace r davis
Sent: Saturday, November 10, 2007 7:00 PM
To: atm@atmlist.net
Subject: [ATM] light weight mirrors

I am looking for people that would like to share information on
developing new low cost large light weight mirrors
My idea is 1 inch front thickness  for 20 inch dia with a ribs 2 inch
high but must line up with flotation cell. 1.25  inch thick for 24 inch
dia with a ribs 2.5 inch high and 1.5 inch thick for 32 inch dia with a
ribs 3 inch high. It looks  like the glass will need to be fused to the
ribs from the information I have got from the ATM sits. The cost of
mirrors and weight of telescopes is hampering the number of large scopes
in the ATM world we can change that.

Ribs may not be necessary. I've seen 30" mirrors of 1" plate on the web and
heard of a 32" out of 1" plate. Compared to these a 20" wouldn't be tooo
hard.

Mitch
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