[ATM] Re: RTV Considered Harmful

[sayre at foothill.net (Bruce Sayre)]

On Mon, 9 Feb 2004 23:11:41 -0500 James Lerch wrote:

>...after much fiddling with sling position, and one other "off the
wall" idea, 
> we ended up attaching springs to the back of the optic...

By looking at your interesting and novel cell's picture, it seems the
glass whiffletree was suspended on three bolts far from the cell's wood
ring. By detaching the mirror and implementing a sling for lateral
support, you apparently isolated the cell's bending effect from the
mirror.

If your whiffletree had been directly attached to a more rigid metal
base, like Steve Houlihan's, with the collimation bolts attached
elsewhere, do you think you would have eliminated the distortion caused
by the cell? Or do you think that failure was inherent in the
optic-RTV-glass whiffletree structure itself, not how it was suspended
on bolts or because of the wood? Do you see any essential differences
between Steve's cell and your? 

Build big binoculars!

Bruce Sayre
P. O. Box 544
Applegate, CA 95703 USA
mailto:sayre@foothill.net
http://www.foothill.net/~sayre