Re: [ATM] Spherometers and sphericity

[Jim Burrows <burrjaw@earthlink.net>]

At 2007-11-28 18:57 -0500, Francis J. O'Reilly wrote:

>I never do any testing of the surface
>whatsoever until I am fully polished out. I made an exception  to this rule
>a couple of months ago when I went to Guy Brandenburg's telescope workshop
>in at the Community Center in Chevy Chase, DC. I put my 12.5 inch f/7 mirror
>on Guy's test stand after I had about seven and a half hours of polishing
>completed.  I have now put another seven hours of polishing
>into the mirror.

Since figuring is polishing, it makes sense to me to start testing 
after you're sufficiently polished to do a test (a couple of hours 
should be plenty).  That way you can learn what works (stroke, 
pressure, MOT, TOT, lap hardness, etc., etc.) in the figuring game to 
get what you want - a polished AND figured mirror.

         -- Jim Burrows
         -- http://home.earthlink.net/~burrjaw
         -- mailto:burrjaw@earthlink.net
         -- Seattle N47.4723 W122.3662 (WGS84)

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