Re: [ATM] Raised zone

[Mike Lockwood <melockwo@uiuc.edu>]

Matheus,

mjlazo@ifsc.usp.br wrote:
> I am trying to make a sphere before parabolizing. The shape of the rest of the
> mirror is a sphere with a 1/2" wide central cavity with less than 1/4 wave. I
> have checked the mirror with a Ronch grating of 100 lines per inch and with a
> Foucoult tester. Because the raised zone is so close to the edge, I do 
> not know if the edge is turned down in relation to rest of the mirror. I think
 > that the method 6 of Jerry

Since you are spherizing, working with your finger is not necessary.

Portion of Jerry's message:
>>If you insist on working MOT you can achieve the same result pressing
>>on the side of the mirror NOT overhanging.

I definitely recommend the MOT version.  You are less likely to turn 
the edge that way.

A variation I like is to center mirror on top of the lap, apply 
pressure to the side of the mirror nearest to you (the trailing edge), 
and then push the mirror away from you while applying moderate 
pressure.  Then re-center the mirror on the lap without pressure. 
Rotate the mirror, take a step around the barrel, and continue.

If you already have a turned edge before doing this, it may or may not 
cure it.

	Mike Lockwood

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