Re: Alternative mirror technologies, WAS ATM Liquid-mirror telescopes

[Chuck Knight <cknight@flash.net>]

Kurt Hillig wrote:
> Of course if you're interested in image quality, rather than making a
> solar furnace, then the top surface of your embroidery hoop had better be
> flat to 1/4 wave....

Actually, I got it for a cheap circular form for some spin cast mirrors
I was making.  Works great, and is a lot cheaper and easier than 
manufacturing a form with the same diameter, from scratch.

But, for the purposes of this project, I am not interested in image
quality.  I *am* interested in seeing how close to a parabola I can
get...in subsequent generations I can focus on image quality.  If
it's nowhere even near a parabola, I probably won't pursue additional
experiments.

Think about it...If I was interested in ultimate image quality, at 
this stage, I wouldn't be using an embroidery hoop and a mylar balloon 
for the initial prototype.  :-)

First things first...

> Trust me, it it were this easy, someone would have done it already!

Usually this is true, but since I can't find much documentation on
this technology, I don't know if many people have actually tried it.

Also, most references to it have been of the type "Has anyone ever 
tried..."  I've found only 1 reference to vacuum forming mylar, and
it implied some reasonable results.

I have a feeling that it wasn't "flat aluminized mylar" that was used,
though.

     -- Chuck Knight