Re: ATM Big scopes

[Richard Schwartz <richas@chelsea.ios.com>]

-- [ From: Richard Schwartz * EMC.Ver #2.5.02 ] --

Uh... if you slump your blank, the taper at the edge is no problem at all. 
The glass will sag down to the slumping form.  So there is no reason not to
use the full 48" width of the sheet of glass.

Note that annealing must be done after slumping, so there is not value in
getting a fine annealed pyrex if you slump it.  Just go with cheaper un-
annealed glass.

I suppose you want the focal length long enough that you don't have to
parabolize your 48".  You will also need a pilot's license for the hot air
balloon, and an oxygen outfit for the altitude.

Even if worthless as a telescope, such a mirror might be wonderful for
infrared observations if equipped with the right sensor.   And it would make
a hell of a solar concentrator!