Re: ATM Am I done yet?

[Douglas Braun <doug@dougbraun.com>]

Well I went back to work.  I spent 30 minutes getting rid of the center hole with a small lap,
and then I did 30 minutes with the full-size lap and a 50% W stroke to smooth out
the irregularities.  At that point I expected I would need  half a dozen more figuring sessions
to get it where I wanted it to be.

But I lucked out:  Under the Foucault tester, the surface looked really smooth, and a couple of
tests (analyzed with Sixtests) showed 0.991 Strehl and 4.1 nm RMS surface error.  More
importantly, the star test looked real good: I could hardly see any difference between 
the intrafocal and extrafocal images.

So it's off to the coater next Monday.

To avoid any chance of second thoughts, I gave my lap a few good whacks
with a sledgehammer.

Doug Braun


At 09:48 AM 9/18/02 +0200, you wrote:
>Douglas,
>>So despite the good looking numbers (which tended to change significantly
>if I re-tested with the mirror
>in a different orientation), I decided to smooth out the mirror and
>re-figure it.
>
>
>I will reconsider decision to smooth out the mirror
>which is 0.99 Strehl.
>First I will check measuring system and try to get reproducibility out of
>it. Then, and only then,  will
>I touch the mirror. If you do not believe
>the test apparatus and its results then what's left?
>
>Regards
>Vladimir.