Re: OWLS Anisotropy Proven Beyond Doubt.

From: N:dlzc D:aol T:com \(dlzc\) (net_at_nospam.com)
Date: 08/22/04 

Date: Sun, 22 Aug 2004 08:27:14 -0700

Dear Max Keon:

"Max Keon" <mkeon@ozemail.com.au> wrote in message
news:412897DD.7DCD7188@ozemail.com.au...
> Myxococcus xanthus wrote:
> >
> >Max Keon <mkeon@ozemail.com.au> wrote in message
news:<411D8559.C63EED4A@ozemail.com.au>...
> >> http://www.ozemail.com.au/~mkeon/alaser.jpg is an arial picture
> >> of the apparatus. Now you have the key to the real universe.
>
> > I do not often see plywood and particle board sheets used in the
> > construction of precision optical interferometers.
>
> You know a lot about handling lasers then?
>
> Normally, I find that particular construction very adequate. My
> problems have arisen because I decided to split the beam with the
> edge of the prism instead of a semi silvered mirror, as I would
> normally use. And I was looking for an enormous 1.4 fringe shift,
> not the usual minute shift that has required me to sit quietly in
> a dark room for hours staring at the screen mounted on a very
> similar setup to the one I've used here, but not incorporating the
> "edge beam splitting" method, trying to notice the vaguest pattern
> variation. Don't try to tell me that that setup is not adequate.
>
> The edge beam splitting method would amplify any mechanical fault
> dramatically, as it did. But the story doesn't end there. The
> directional preference of the apparatus for the east-west
> orientation of the left-right pattern shift maxima was still
> emerging beyond the mechanical faults.

Wood has a very high coefficient of thermal expansion, so variations in
temperature will provide a shift.
Wood has a lot of geometry change due to absorption/loss of moisture to the
air, so the humidity history (like breathing on it, as well as ambient
weather) will provide some interesting results.
Wood also has a great deal of hysteresis (being the world's first composite
material), so positioning history will have an effect also.

Keep in mind that a solar heated wall, such as the west wall during the
night, will provide a temperature gradient anisotropy.

They make these things out of granite and metal for a really good reason,
and to increase cost is not the reason.

David A. Smith

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