Re: ATM Mirror support -- the ultimate?

["Bill Prewitt" <bprewitt@neo.rr.com>]

Actually, this idea is more promising than you'd think.
big disk can be set to float a couple of thousandths above the plate.
(Bernoulli is your friend)

You'd need to polish the back of the mirror, and rest it on a 1/4" aluminum
plate having a few dozen 1/16" holes through to a plenum.
I doubt if you'd need much flow at all.
You would want to reduce the pressure when tilted to the horizon.

I haven't actually tried this with glass, but  I remember seeing it on a smaller
scale in a factory process.

Here are some air table links if you want to play with the idea.
http://www.intelligent-imaging.com/marianas_web/airtable.html
http://www.multiconveyor.com/airtable.htm
http://www.microtec.net/srp/tablan00.htm
http://polaris.phys.ualberta.ca/users/singleton/demos/Mechanics/HTML/coriolisdef
lectionairtable.html
http://www.glasgowproducts.com/apps.htm

         Bill Prewitt
My webpage of telescope making and caving
http://home.neo.rr.com/imaging

> >
> > I wonder, has anyone considered combining fan cooling of a very thin
> > mirror with the ultimate multipoint floating support: an air cushion?
> >
> >
> > Comments?  Large gaping holes in the idea?  Or is this another "this was
> > done twenty-five years ago, and one does it any more because of this
> > major problem" sort of idea?
> >