ATM Testing Diagonal Flatness

[Bill Marriott <btk@pacbell.net>]

Hi folks;

A couple of weeks ago,  there was a brief thread on the flatness of
diagonals as to how flat should they be...

After a brief discussion with Mel, and with his approval, I have the
following offer to make:

I manage/part own a small precision optical shop, and we have a Frizeau
interferometer set up for plano work.
It was built by a now retired engineer from Tinsley, and while it is not
a Zygo, it has a decent reference flat (supposedly 1/17th wave, when the
Bk-7 flat is stable)

I am proposing that those of you that are interested, if you wanted to
send me your flat, I would be happy to do a ball park test and
catagorize the flatness (over two axis) as say >1/2, 1/4, 1/8th, or
1/10th wave or better
(PV) While I do have fringe anayliss software, it is fairly
tempermental, and has a problem with the somewhat grainy image produced
by our interferometer, and takes me quite awhile to generate test
results, so for the purpose of this test, eyeball will have to do (I'm
fairly good at calling out realistic results this way).

Why would I want to subject myself to dealing with this?

One reason is as a producer in the past of diagonals, I find it very
interesting as to what comercial endevors are sending out as flat
diagonals.

It would also be nice to come up with some hard numbers as to what is
actually available out there, as a guide to future builders. A database
of info could be posted somewhere.

The only costs involved would be return shipping and insurance.

In general, this is sort of ment as a 'fun' exercise, allowing us to
really get an ideas as to what is out there in the commercial elliptical
flat market.

I would like to avoid getting involved in any customer/vendor disputes,
what you do with the information is up to you in that regards...

Those of you who are interested, please contact me off list, so we can
set up a program. If too many people are interested, then it will have
to be spaced out over a couple of months or so.

Bill Marriott
btk@pacbell.net