From wpk@saao.ac.zaFri Jul 17 22:38:43 1998
Date: Mon, 9 Mar 1998 13:58:33 +0200 (GMT+0200)
From: Willie Koorts <wpk@saao.ac.za>
To: Gary Thorup <pthorup@capecod.net>
Subject: Re: Dobsonian conversion/Mount


Hi Gary

Sorry to only answer your mails now - I only have e-mail at work.  Thanks for
the mails and comments on my telescope page.  It is always good to hear 
what shortcomings people find on a page to know how to improve it. 

You said:

> I was wondering if I could get a hold of some specs. for your telescope
> mount.  It is just the one I was looking for.  If you have time, I would
> love to see some more information on it.

I thought of making dimensioned drawings and detailed information on exactly
how I build this before, but decided against it because I thought it would
not help much since someone who would want to copy it will surely have a
mirror of different dimensions, etc.  The present page was thus intended to
give ideas (the same way I took other people's ideas and combined it) rather
than building instructions.  I have no problem supplying specs, advice, etc. 
Exactly what specs, etc. are you intested in?  Any suggestions on what
(specs, etc.) to add to my page to be more useful to others as well? 

You also said:

> I was wondering what the specs. would be for an equatorial mount like
> yours, but on an 8" Newtonian telescope.  My telescope is already in a
> Dobsonian mount and I am trying to put it in an equatorial.  I thought
> your idea was a good one for someone who wants to stay away from
> fittings and pipes.  Any information would be greatly appreciated. 
> Thanks!

I was actually planning to do just that - OK, the exact opposite to the way
you would have to go.  I am planning to also build a Dobsonian base for my
telescope.  To use it in Dob-mode would then mean using the telescope from
the rocker box and up and put it onto a Dob-type base and turntable instead
of the present split-ring and triangular base.  This would leave one with 
the option of using it equatorially (split-ring) or in Alt-Az (Dob). 

Agian, I would probably design as I build once I have a good idea in my head
of how I would like it to be, so I would not have much to show until I
finished.  I suppose it is a bad habit, but I don't really design much on
paper before-hand.  Once I am more or less clear on how it should look and
work, I would start building and maybe draw out the bits where dimensions
become critical.  What you see on my telescope page is about what I drew
beforehand to at least know where to put the secondary w.r.t. the primary. 
To make the spilt-rings, I had a piece of wood of a certian size which is
what determined the eventual size of the rings.  The size of the cut-outs
(where the rocker box rides on) were dictated by the size of the rocker 
box and declination discs which were made already (I basically built the
telescope from the top down). Once the split-rings were made, the base could
be made to fit, also determined by the angle required (my latitude). 

Once you have the basic idea and you start building, things just follow on
each other and it becomes clear how to proceed - 3-d visualising becomes much
easier.  Thank goodness for G-clamps!! 

You are welcome to ask quiestions etc. any time.

Regards
Willie

                       Mr. W.P. Koorts ( wpk@saao.ac.za )    
                     South African Astronomical Observatory 
                   PO Box 9   Observatory  7935  South Africa
                 Tel. (27) (21) 47 0025  Fax. (27) (21) 47 3639
               World   Wide   Web  ( Work ) http://www.saao.ac.za
             World Wide Web ( Personal ) http://www.saao.ac.za/~wpk/