3 years ago I bought a 127mm F9.4 objective from Surplus Shed in the USA,
http://www.surplusshed.com/pages/item/l3967.html
I tried putting it in a tube, but finished up with a very unstable beast, and since then it has sat in the shed!
I'm now playing with the idea of a folded refractor design, to be setup for 'table top' use, on a small Dobsonian base.
My brother in law is very interested in looking through a telescope, but he's a quadriplegic; this design would allow him access, and the rest of the family would probably like it too.
I've managed to source two 100mm optical flats from Surplus Shed.
Folding the light path path introduces just one more surface than a traditional design, and allows for a fixed eyepiece position.
Field rotation?, yes, but I'm only interested in visual, not photography.
I've had a lot of fun drawing up the design in Google Sketchup, which I would recommend to everyone for this type of project.
Google Sketchup can be downloaded from
http://sketchup.google.com/intl/en/download/index.html
A screenshot of my design is attached.
The 'box' is 500mm x 380mm x 180mm, the light path is 1200mm.
The Dob mount provides a fixed eyepiece position 400mm above table top height.
I'm interested in comments from anyone who has tackled a project like this, and any pitfalls that I might not be aware of.
Cheers
Chris