Re: ATM Foucault test accuracy

[Mel Bartels <mbartels@efn.org>]

The commerical shops tend to push out undercorrected mirrors because they
approach parabolization in a systematic manner.  As soon as the mirror has
enough parabolization to fit within the tolerances, it is shipped
off.  There is no point in messing with a mirror that is 'finished' from
their criteria.

The amateurs on the otherhand, being undisciplined in the sense of knowing
the goal but not necessarily a systematic approach, use the screwdriver
and screw method.  Think of a guy with a screwdriver and screw. You KNOW
he's going to overtighten it!  

Mel Bartels