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

["J.O. Williams" <jow@techbase.com>]

> 
> > I could probably build a mylar
> > mirror for even less!  (Say, have you actually tried that vacuum
> > technique, or is it just theory?  I have a 14" embroidery hoop
> > that's just "screaming" for an experiment!  Why would it form a
> > parabola, specifically, instead of a spherical mirror?)
> 
> I've got a question.  I've seen occasional references to mylar 
> film mirrors...pulled into a parabola with a vacuum.  What
> makes it take on a parabolic shape?  
> 
> I understand how a spinning liquid is forced into a parabola,
> but how does the membrane mirror work?
> 
> If nothing else, it sounds like a fun experiment!  Now where
> did I put those mylar balloons?  :-)
> 
>      -- Chuck Knight
> 

Take a look at the July 1997 (page 60) Scientific American.  It is
an article on "Sail Making."  However, the sails are made out of
kelvar and mylar.  The sails are made on large formable shapes. 
A lot of technology is devulged including vacuum shaping.


-- 
J.O.  Williams