Re: ATM A question about Foucault testers

[Brandon Mathew <brandon@core.rose.hp.com>]

Michael P. Linder wrote:
> Yes, the numbers should INCREASE as the knife edge gets FARTHER from
> the mirror's surface.

Thanks.  

> When you do your data reduction, be VERY careful
> of the units you are using.  Remember to put the decimal point in the
> right place when you convert your tester's readings into inches (or mm
> or cm).  Remember to use the radius of curvature, NOT the focal length
> in the computations.  You did not mention what (if any) software you
> are using to reduce the data.  You can get my "Tex" program, or Jim
> Burrows "Foucault" program from my home page http://home.att.net/~mikel
> if you would like.

Thanks for the pointer.  I'm using an excel spread sheet that a local
ATMer who is getting me through the mirror making process uses.  He's
currently on vacation, so I couldn't ask him the question about the
direction of the foucault tester.  He uses a little different mask than
a couder mask, using 1/2" slits at the 30%, 50%, 70% and 95% points of
the radius of the mirror, instead of the knife edge positions.  Since
I'm also using this method, I can't directly use the tex program.
I think I will download tex, print out a couder mask and use it as
well as a double check.

Thanks again for the sanity check.

Brandon Mathew