> If that were true, then it should be possible to build a 6-point floating
> mirror support that would *outpreform* a conventional 9-point floating
> support.
> ...
(with picture)
I don't see why it would be better. Deforming materials are kind of complex.
> Why bother with useless support points inside the edge of the mirror? If
> supporting at the edge only slightly alters the F.L. of the mirror, but
> doesn't introduce astigmatism, or other abberations?
*If* it doesn't introduce other aberrations. That calculation I mentioned showed that you could apply a uniform pressure to a mirror and get a paraboloid from a sphere, without enormous pressures. I assume not supporting a large mirror would introduce spherical aberration.
> I wish I had that Sky&Tel article that had the interferogram results of
> various support points. I only seem to recall that a three point support at
> the edge of the glass had significantly greater P/V distortion than did the
> three point support at the .707 radius. Maybe someone could verify that?
As long as I'm going to say these kinds of things, I'd better check it. I have it at home, somewhere.
Clay