Re: Viewer Focussing Schemes

[Brian Reynolds <reynolds@xxxxxxxxx>]

Robert wrote:
> Alan Lewis wrote:
> > 
> > What if the sliding focus that I use (like in the MF kit) were designed
> > to eliminate having to loosen and tighten the screw, just slide it and
> > it stays? How about a lever on the bottom of the viewer that forms a
> > fulcrum with maybe a 3:1 ratio for finer adjusting?
> > 
> > Let's talk.....
> 
> Make sure this does not happen off list. Lots of us are interested.
> 

You might want to try something like the Crayford focuser that amateur
astronomers use.  You can see an example at:

<URL:http://www.atmpage.com/cray.html>

Have the inner box rest against some telfon pads (ball bearing in a
Crayford focuser) and an axil attached to the outbox with a wheel that
bears against the inner box.  Turning the axil focuses the viewer.  A
set screw could provide for a focus lock.  There would be no gear slop
and it's easier and cheaper to build than a rack and pinion focuser.

-- 
Brian Reynolds                  | "Dee Dee!  Don't touch that button!"
reynolds@xxxxxxxxx              | "Oooh!"
http://www.panix.com/~reynolds  |    -- Dexter and Dee Dee
NAR# 54438                      |       "Dexter's Laboratory"