Re: [ATM] my first Foucault look-see-semi-test

["Bob May" <bobmay@nethere.com>]

First off, pitch is sort of like silly putty in it's action.
Move it slowly and it flows while higher stresses make it break
up.  I've never heard of flax seed oil being used for softening
pitch but it may work.
It is always a big thrill to really see the image of the mirror
the first time with the Foucault test!  It never ceases to amaze
one when you think that you are measuring a surface that is
different by only a small portion of a wave from the rest of the
surface.
It sounds like you have either a hole or a hill in the middle of
the mirror and, if a hill, it is easy to get rid of by local
pressure as you polish.  If it is a hole, you'll be needing to
take care of most of it before starting parabolizing.
Good luck and keep up the good work!
Bob May
bobmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
Replace the obvious words with the proper character.

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