Re: [ATM] New minimalist single-pole 18" ultralight

[Michael Lindner <mikell@optonline.net>]

Ross Sackett wrote:
> There is another kind of rocking you might mean,
> though--on the altitude axis itself.  In my four
> scopes using this design I've never experienced
> anything like that...

This is what I meant. With a "traditional" dob alt support, there is a 
rectangle formed by the 4 support points. The three points of support 
form a triangle 1/2 the area of that rectangle, and in a tilted plane. 
Obviously forces that moved the "apparent center of mass" outside this 
triangle would cause this scope to tip, but even a lesser force will put 
more force on one support point and less on the other 2, which could 
cause flexure or roughness of motion.

It sounds like you're not experiencing that, so your design and 
construction are superior to the prototype I played with. Kudos!

>> Also, the single pole looks like it would be
>> a source of flexure 
>> and be bouncy when the scope is moved.
> 
> Vibration is another matter: with the long
> cantilevered arm it takes 3-4 seconds to settle down
> after a rap with the knuckles, which could be too much
> for some people.

Sounds like you have this solved too. The problems I've seen in 
cantilevered scope implementations are vibration at the eyepiece and 
flexure that compromises collimation when you change altitude, 
especially with heavy eyepieces.

And lest I sound like to much of a curmudgeon, congrats on the scope!

Clear skies.
-- 
Michael Lindner
http://www.starastronomy.org *** http://home.att.net/~mikel
http://www.atmsite.org *** http://www.atmlist.net
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