Re: [ATM] Flat Testing

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

Look at it this way - as you press on a part of the glass, that part is
being driven closer to the other piece of glass.  Thus, if the glass is
convex, a press on the edge will make the fringes move towards the pressure
area as the distance between is growing smaller and the fringes are
spreading out towards the pressure point.
Also note that the comparison between the two peices of glass are relative,
not absolute in flatness.  The test is equally valid with a 20" radius of
curvature on both pieces of glass.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net


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