Re: ATM 6" Dob: How Easy? How Cheap? How Heavy?

["Guy F. Brandenburg" <guyfbran@erols.com>]

John Stewart wrote:

> Brent Hutto said:
> > ... I'm visualizing a slightly more elaborate
> > design with thinner plywood but square pieces of wood inside the
> > corners so that no screws have to go end-wise into a piece of
> > plywood. Is that commonly done?
>
> Yes.  FYI, here is a photo of me and my 6-inch f/6 hexagonal scope:
>
> http://www.erols.com/thestewarts/images/johns6in.jpg
>
> My only regret is that I should have made the tube larger to give more
> clearance.  I have a couple of other photos (of the mirror mounts), but
> haven't scanned them in.  The walls of the OTA are wood paneling I had
> lying around.  The corner pieces I "machined" using a radial arm saw
> with a shaper attachment set at the right angle.
>
> Jerry Wolzanski (of the Northern VA. Astronomy Club) has a 6-inch f/15
> built with a square cross section with corner pieces.  He cut the tube
> in half and joins it using dowels inserted into the corner pieces.

I built one that can be broken down to take on airplanes based somewhat on
Jerry W's design, myself. If I recall correctly, he (and I) put pieces of
PVC pipe into the corners that dowels go into. The PVC pipe really does NOT
hold the corners together; it's mostly glue and nails. But there are
baffles every so often along the tube, much as in Richard Berry's 6" f/8
scope in his original book.

I also made another scope (for a high school) using really thin hardboard
(about 1/4" thick, also known as masonite) and pieces of regular lumber in
the corners for strength, for the rocker box. It works; it was supposed to
be more-or-less portable.