From: Michael Lindner 
To: atm{at}shore.net
Reply-To: Michael Lindner 


On Thursday 31 July 2003 02:04 pm, mlbrown{at}everstrive.com wrote:
> However, it is easily tested; apply a load and measure the deflection.

...which is what I did several years ago. The mirror is a 13" coulter
mirror (approximate weight 13 pounds). It is attached to the mirror cell by
six 1"x1" square pads of GE Clear silicone II, 1/8" thick.

A dial indicator was mounted on the mirror box and shaft placed against the
mirror. Scope was rotated from zenith to horizon. The only detectable
movement was a 0.003" lateral shift (shear), when the scope pointed at
the horizon. There was no detectable movement along the optical axis.

Note that since this test measured deflection of the mirror relative to the
mirror box, the deflection is the sum of any slop in the collimation
screws, the teeter-totter bars, and the silicone, so 0.003" is an
upper bound.

Obligatory Netiquette tip (not directed at any one individual): Please
don't include the entire message in a reply - only a few relevant lines.

--
Michael Lindner
http://www.starastronomy.org
http://home.att.net/~mikel http://www.atmsite.org
http://home.attbi.com/~dcass/atmfaq/atm-faq.htm

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