[ATM] Re: Laser People and Constructing Telescopes

[Jay Kirkland <jaykirk@compusmart.ab.ca>]

Been reading some comments largely dismissing the laser and thought I'd
just speak up in defense of this wonderful invention. I've just re-built my
four scopes and my LaserMax has been  a wonderful aid in the process. The
first thing I used it for was to square the focusers on the tubes. First I
drilled a tiny hole in the tube precisely opposite the center of the
focuser. Now I know this can be done with a site tube, but it seemed
somehow so much easier to shim the focuser while watching the laser dor
center over that hole. I also used the laser to center the  spider and the
diagonal. Again something that can be done with a site tube but the laser
was handy and again watching that dot come to center seems easier. 
	But it was on my 20" f5.7, that I first used the laser to center the
spider cage over the mirror box. I have no idea how I would have managed
this accurately w/o the laser. It would probably have involved up and down
ladders, measuring and shimming, possibly a plumb line after everything was
perfectly levelled, and how do you level something like that? In old
Telescope Making mag, someone used a large mirror over the front of the
spider cage to create a kind of giant autocollimator or something. With the
laser I did it quickly and easily. And what's more, I discovered that the
scope did not re-assemble with any kind of repeatablity. The trusses
slipped ever so slightly when the scope went back together or moved  in
altitude and azimuth (no matter how tightly I clamped the poles), moving
the laser dot around an area maybe an inch in diameter, Something I never
would have suspected and easily fixed with tiny bits of emery cloth contact
cemented into the upper truss clamps. Now they hardly have to be tightened
and both in re-assembly and use that center dot remains precisely centered. 
	When I built the scopes, I took care to build all the wooden components as
perfectly squared as I could, so that the joints will be tight and strong,
so that nothing binds or rubs, so that my digital setting circles will be
accurate when I use them, so that my equatorial platforms (when I finish
them) will track accurately. I used all the tools at my disposal to do
that, not that it needed a lot. The laser proved invaluable in continuing
that process in the squaring of the invisible bits that I couldn't measure.
Contractors use laser levels to do practically everything now. And now I
can't imagine building a scope, at least a truss tube scope, without. 
	As for collimating, I use mine to square the primary under the secondary,
then roughly collimate, and then I use the Cheshire to finish. I don't know
if it's faster or not. Seems so. Haven't tried the barlowed method yet. 
	But if you're building a truss tube scope, especially one that
disassembles, or if you're even thinking about building any kind of
rotating eyepiece/spider cage assembly, by all means borrow a laser from
somebody. It makes construction so much easier and allows you to do things
that maybe you'd never think of doing otherwise, that maybe aren't even
possible otherwise. 

Confirmed Laser Boy 

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