Re: Building first dob - questions

From: Dennis Woos (dpwoos_at_gmavt.net)
Date: 10/23/04 

Date: Sat, 23 Oct 2004 18:41:50 -0400

> - What's the optimum eyepiece height to design the dob at? I observe
> with my little Mak-Newt using a drummer's stool, but the dob is going
> to be much higher. So do you try to design it to do most of the
> observing standing or sitting? I'm relatively short at about 5'7"
> tall.

You don't want to ever use a step stool/ladder if you can help it, so try
and build it so that you (and those most likely to observe with you) can
comfortably look through the eyepiece standing when the scope is pointed
nearly straight up. Then, you can use an adjustable observers chair
(commercial, homemade Denver, etc) to support your backside when you are
observing lower.

>
> - What's the optimum eyepiece angle? Do you normally set the eyepiece
> axis to be parallel to the ground, or do you orient the secondary cage
> so that it tilts up a few tens of degrees?

We like 45degrees. A great feature is a rotating upper assembly, but this
is hard to build in such a way that collimation is preserved.

>
> - Why the widespread use of Baltic birch and apple ply?

No magic here. Baltic birch/appleply is much better than regular plywood,
but there have been plenty of scopes made out of other materials.

Most important is to get the bearings right, i.e. no stiction. I would
stick with Ebony Star and Teflon unless I was willing to research/experiment
and make modifications.

Dennis

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