[ATM] Need Advice on Mounting & Driving a 16 Inch Newtonian

["David Sleeter" <d.sleeter@roadrunner.com>]

Hi Folks:

Though I've owned telescopes since the 1960s, I'm a "newbie" to telescope
making. I've never ground a mirror, and though I have a complete machine
shop at my home, I've never used it to build a scope.

Back in 1990, through a remarkably lucky sequence of auction purchases and
subsequent trades, I ended up with a 16" F-6, full thickness, solid zerodur
Newtonian mirror and diagonal, diffraction limited, and custom made by Jerry
Brunache. It's been sitting in a closet for 16 years, I'm finally thinking
of mounting it, and I have some "newbie" questions.

1. I'm CERTAIN that I want to make a computerized "Go-to" scope, but should
I mount it equatorially, or make a computerized alt-azimuth mount (like my
Nexstar 11 GPS)? I see advantages and disadvantages to both designs. For ME,
at least with my limited understanding, the advantage of the altazimuth
mount is simplity of construction and ease-of-use for visual observing (no
need for a rotating cage for the diagonal and eyepiece), but it introduces
the problem of field rotation when doing long-exposure astrophotography.

On the other hand, an equatorial mount eliminates the problem of field
rotation for photography, but it requires the construction of the rotating
cage for the eyepiece & diagonal, and overall use for visual might be less
convenient.

But then again, I THINK I've heard that today's image-processing software
can compensate for field rotation. If that's the case, I'd definitely settle
on the alt-azimuth design. Your opinions?

2. Regarding the drive, about 20 years ago I bought (brand new) all but the
motor and clutch for a Byers 12" drive for a 12" telescope project that
never materialized; I can buy a motor and make the clutch myself. In
debating whether or not to keep this 12" Byers drive, I need to know if it
would be practical or desirable to use it as one of the drives in my
contemplated go-to scope (as the polar or dec/altitude or azimuth drive),
and if so, is there a commercially-available combination of motor and
software that will make it work in a go-to system?

3. Finally, I'm looking for good ideas on the scope's general construction.
I have a machine shop so I can make just about anything. but I'm
up-in-the-air about things like how to make the tube/truss assembly, and how
to make the forks (either equatorial or alt-azimuth, it will be
fork-mounted). If you know of someone who has a good design for a scope like
I'm contemplating; someone with a website illustrating what they've done,
I'd greatly appreciate a link or two.

A final note; I do NOT plan to make this scope portable. It will be
permanently mounted in a back-yard observatory (yet to be built). Any advice
on these matters would be greatly appreciated,

David Sleeter/Moreno Valley, CA


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