Re: [ATM] Mak-Cass OTA mechanical design

["Don Clement" <clement.focuser@verizon.net>]

Hello David,



The primary for the f10 8" Max Bray Mak-Cass optics has a 50mm central hole.
The primary was made from a surplus Pyrex ribbed blank left after production
ended for the old C10. I mounted the primary on an aluminum arbor/ baffle to
a moving mirror focuser. The focuser is fixed to the back end plate of scope
by means of a coaxial collimator. Because the secondary is a third curve
polished directly onto the inside surface of the corrector, collimation is
made by tilting the whole focuser with primary from the outside end plate by
use of three coaxial collimators.  I spring loaded the moving plate of the
focuser to the spherical end of a standard 1" micrometer head. This system
works extremely well having zero image shift, no backlash, no mirror flop
and needs no lubrication. The problem of mounting and focusing the Mak-cass
optics was in fact the reason that I developed my compliant focuser. The
original focuser prototype (with the Stanley tape measure compliant hinges)
is still working in my 8" Mak-Cass.



Don Clement

Running Springs, California

http://www.clementfocuser.com


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