Re: [ATM] TOT and oblate spheroid:

[Mike Lockwood <melockwo@uiuc.edu>]

Mark,

Not sure if you got a reply to this - I would suggest TOT with a more 
standard stroke (less side swing).

What are the size and focal ratio of the mirror you're working on?

TDE is a sign of poor lap contact, excessive pressure when the mirror 
or lap are overhanging, or sometimes polishing when the slurry is 
quite dry near the edge.

	Mike Lockwood


Mark Clement wrote:
>  I recently used a suggested method for bringing an oblate spheroid
> closer to a sphere, with generally positive results: a roughly spherical
> figure with a narrower TDE. I have managed to achieve this in the past,
> on mirrors from 4.25 to 12.5inch, albeit with a rougher surface and at
> the expense of more fussing. Fixing the remaining TDE by using standard
> methods created additional problems, this without eliminating or reducing
> the defect. Continuing with the stroke (TOT 1/2 side-to-side;1/3
> long) that brought me to this point doesn't seem to be the way to go,
> since the original figure no longer exists. How might I best attack the
> TDE? Regards, MC


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