From: "Andreas Derwahl" 
To: "'Mel Bartels'" , "Atm-US
\(E-mail\)" 
Reply-To: "Andreas Derwahl" 


Hi Mel,

truly great looking scope!!! I like how you kept to the triangluar symmetry
throughout the scope, starting from the azimuth bearings -> altitude b.,
6 pole truss assembly, OTA and wire spider.

Someone raised a question on a german newsgroup, if the wire spider is not
vibrationally inferior to a standard excentric design. Especially
transversal vibrations along the optical axis seem to have been a problem
in some attempts. Does using aluminium channels to seperate the eyebolts
and crossing the wires get rid of that problem?

For my 10" travel dobson I would like a four vane wire-spider on a
single upper ring, with the tension being generated at the secondary holder
and the wire loops just being hooked into the ring. I'm now wondering if
that will induce hard to handle transversal vibrations, if the wires of a
spider vane form a triangle, joining at the single OTA ring?

It is not so clear to me, but it looks like your wire arrangement is
actually a four vane spider with two vanes meeting at one corner of your
upper triangle. Am I getting that right?

Thanks for sharing your inspirational scope with us,

Andreas

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