Re: [ATM] Initial large thin mirror grinding question

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

The latest clever technique is to lay the mirror down and use a
small diameter iron tool to make the depression (hole) in the
mirror to close to where it needs to be.  Then, using one of
several different methods, cast a tool for the mirror.  The
original intent of the cast tool was to make a cheap alternative
to using another piece of glass in the old traditional method
that Howard shows but some have tried their best to make the
process much more difficult and expensive than just using another
piece of glass.
As to MOT or TOT, it depends upon the direction that I need to
take the ROC of the surface.  MOT tends to decrease the length of
the ROC while TOT tends to increase the length of the ROC.
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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