Wow some great ideas in this one. And something I think I can actually build even with my two left thumbs.
Since the OP's thread has been hijaked of topic a bit, although with some awesome ideas. Could I suggest a new thread to take this further. There are I am sure a few kits like this and neat "devices" that make construction simple. All we need is to collect some ideas and maybe get someone to do some CAD drawings, with materials you can buy from Bunnings and similar places.
"The Iceinspace DIY Kit Observatory".
I was thinking of comnining the GeoDesic concept with this Star plate connectors. Make the Geodesic frame from wood using the Star Plates to form the Pentagons and Hexagons, or something similar to give the right shape (maybe have to come up with this). Then you just nail on some Panels (add some Water proofing) to the frame and pannels and you can have a Dome. Look I am not the best at this but I hope you get what I am saying. Thos in the consturction game couls suggest easy to get materials that would be suitable for an observatory.
Also as to the loss of space due to sloping walls, well they seem to have thought of that, to give you straight walls.
http://www.strombergschickens.com/st...stem_self_scaf
Regards
Fahim