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

[Dave Smith <smithersscope@yahoo.com>]

Yeah, just use mylar (from one of those "over 40" or
some such balloons) and you won't even have to have it
coated!

Spent the day with a friend from work piddling in the
garage; almost finished the binoc mounts (tripods and
parallelograms for his 10x70's). He had to head home
right after dinner. Shame...First night in weeks we've
had clear skies here on SoCal...finally got to see
Holmes through my 16" scope. Wow! The sucker barely
fits in the FOV with my 52mm Rini!! Too cool. Had the
kids hootin' and hollerin'.

Dave


--- Richard Schwartz <richard1941@gmail.com> wrote:

> 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
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 


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