Re: Slow Dobsonian
Dianne Van Gemert (dvangeme@edcen.ehhs.cmich.edu)
Sun, 5 Mar 95 17:11 EST
>
>I am in the process of converting the mounting of my old 1936 Newtonian
>to a Dobsonian, which will make it more portable, inter alia.
>What material can I construct the base from, since the side supports of
>
I've found that 3/4 in plywood works just fine on any rockerbox sides
that I've made up. I'd leave the bottom of the rocker a bit oversize at
first, then if it seems flimsy to you, put perpendicular stiffeners on
the sides, which will really reinforce it without adding the weight of
another layer of plywood. Don't judge your stiffness by weight, tho.; see
if you get any backlash when you slew the telscope in azimuth (check it
with about a 18mm eyepiece and it'll show up blatantly), because that's
what will really decide the matter for you. If it's sturdy enough without
the outside stiffeners(I bet it will be), cut the base down so it's less
to stumble over.
Also, if you make the "front" board of the box as high as possible(still
allowing your tube to reach the horizon, or a few degrees lower) this
will add a LOT of stiffening(by the way, make this out of 1/2 or even
1/4in plywood-you'll save more weight without losing effect).
Sounds like a nice project (7 foot, eh?)