Re: ATM Mercury flats

[kevin@aquilagroup.com (Kevin Ferguson)]

At 10:47 AM 5/1/97 -0700, Spencer Roedder wrote:
>  For mirror diameters in the amateur range, this
>curvature is way too small to matter.

And even for larger optics.  Though it shifts the focus,
a fair amount of spherical power is tolerable in an
autocolimation flat, provided it is zone and astigmatism 
free.  

I think the real problem with testing really huge optics
this way is in coming up with a way to safely suspend
them above the liquid without inducing mechanical strain
.... a non-trivial problem even for amateur-sized optics.

-Kevin