Re: [ATM] Figuring question

["Jerry" <wa4guu@verizon.net>]

The distance to the edge of the mirror is the same as to the center of the
mirror when it is spherical.  If it isn't spherical, you have the tester
there.... measure the sag difference. Put the end of the tape at the tester
and the edge of the tape goes past the edge of the mirror and you can see
where on the scale of the tape it coincides. More precise and less chance of
scratching the mirror. Just don't knock the mirror off the stand.

Jerry



-----Original Message-----
From: Mark Holm


2. It's not hard, if you can dragoon someone in your household to hold
one end of the measuring tape, to measure the ROC to 1/8 or even 1/16
inch precision.  Wrap a piece of masking tape around the end of the
measuring tape so it won't scratch the mirror, and have your assistant
hold the end of the tape just touching the center of the mirror.

-- 
Mark Holm
mdholm@telerama.com

_______________________________________________
ATM mailing list http://www.atmlist.net/

_______________________________________________
ATM mailing list http://www.atmlist.net/