re: [ATM] diagonal flat testing

[Thomas A Simmons <tasimmons@raytheon.com>]

Jerry,

  I sure hope you didn't touch that mirror.

You said that the mirror had a good STAR test, but your Foucault
tests are not in agreement between the years...and you're not sure
of which FOUCAULT readings to believe?

Trust the STAR test, Luke. There is no better or more accurate test.

Go back to testing your secondary. STEP AWAY FROM THAT PRIMARY!

Tom
Tucson, AZ


Date: Fri, 30 Apr 2004 20:41:18 -0500
From: "Jerry B. Hillman" <JBHillman@ev1.net>
Subject: Re: [ATM] diagonal flat testing
To: "Bob May" <bobmay@nethere.com>,        "atml" <atm@atmlist.net>
Message-ID: <002901c42f1d$66d4ddc0$ff67fea9@ev1.net>
Content-Type: text/plain;            charset="iso-8859-1"

Hi everyone,
Looks like I didn't do the test right.  Diagonal mirror was in the wrong
position.  Should have been close to primary mirror rather than close to
light source. I'll have to try it again.  I have a worse problem.  Foucault
readings last night on the 16.5" primary do not even slightly resemble the
readings I was getting last year.  Current readings put the mirror at .03
strehl ratio. 1/0.722 pv error.  In a nutshell, junk.  Since I haven't
polished on the mirror since the readings I got last year, and the only
difference is that the mirror cell was rebuilt, perhaps the difference is
due to the mirror cell. Regardless, I don't know how to fix this since I
now
can not trust any Foucault readings I take.  Star testing did not indicate
such a poor figure. I guess I won't be sending it off to be coated after
all.
Clear skies, Jerry

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