From: "Don Clement" 
To: 
Reply-To: "Don Clement" 




>     I hope you are not suggesting that you forgo the option to adjust the
> tilt of the primary! Attempting to achieve collimation by bringing all the
> other elements together in line with the pimary will make you crazy in
short
> order. The primary tilt adjustment should always be the last adjustment
made
> and is by far the most critical. Never build a reflector without the
option
> to adjust the tilt of the primary mirror. (Do you hear that Meade? Do you
> hear that Celestron?)

I thought this might be of interest to those building mirror cells.
Illustrations of my coax collimator are posted at:
http://groups.yahoo.com/group/makingyourowntelescope/files/Coax%20Collimator/

The coax collimator was a design for collimating a moving mirror focuser
that I built and installed in a C14 Fastar. The collimator allowed the
entire focuser with 14" mirror to be tilted and collimated from the
outside rear of the telescope. The coax collimator design may be useful for
mounting the secondary or the main mirror for a Newtonian. The collimator
uses no springs.

In the illustrations the triangular plate is the base of my focuser, which
replaced the original C14 sliding tube focuser. My 1" thick focuser
fit inside the telescope tube between the 14" mirror and rear casting.
Shown in figure 1 is the triangular base that three ¬" SS allthread
rods (shown in green) are threaded into. Each threaded rod fits into a
countersunk hole. Or alternately a spherical hole made with a ball end
mill. Fig 2 shows the same triangular plate with two additional components,
the 3/8 rod (shown in gray) and the ¬"acorn nut (shown in red). The
3/8 rod is made from 3/8-24 SS allthread. A 19/64 hole is drilled axially
through. The end of the 3/8 rod that fits into the triangular base is
machined spherical. The opposite end has a countersink hole drilled. Or
alternately a spherical hole made with a ball end mill. Also hexagonal
flats were machined on this end. The ¬" acorn nut is made from a SS
¬" acorn nut and drilledand tapped through. Figure 3 shows a backplate
added to the assembly. In the backplate are three 3/8-24 thru tapped holes
that the 3/8 rods thread into. On the C14 these holes happen to coincide
with the lock down stud holes for the original focuser.

To make adjustments, adjust the 3/8 rod using the hex flats while
simultaneously adjusting the acorn nut. This is coax push pull arrangement.


Don Clement
Running Springs, California
http://www.clementfocuser.com

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