ATM Radius of Curvature! ACK!

[BRYAN LEENHEER <BLEENHEE@millersqa.com>]

Hello everybody,

I just figured out that the sagitta of my four inch f/12 will be .020"!  How
am I supposed to get this small amount of glass out of the middle of the
mirror?  I made the radius checking tool that Texereau recommends, but
the curve is so shallow that I can't even tell that it's there!

Amybody want to take bets about how many wets it'll take to get this
ground out?  

By the way, I've decided to forgo the radius checker and just do the
sunshine test.  

Later!

Bryan