The tube consists of three parts: the upper and lower tube sections and the “truss system”. I worked on these three sections in parallel and so I’m dividing my description on this page into four sections: General Remarks (including altitudinal bearings), UTS, “truss”, and LTS, in that order will follow general remarks. [German ATMers call the upper tube section “the hat” (der Hut); I slip into that below sometimes.]
2014.08.11. I’m back from my summer travels and returning to the Schall von Bell project. I’m at the point where I should be designing the tube. My mirror is ready for a star test, and for that I want a tube. The mental image of the tube involves upper and lower tubes connected by struts.
2014.08.22. I’ve made some wood purchases: some maple plywood, 1/4″ and 3/4″ was available at the local home improvement store. From a nearby hardwoods lumber yard I found 5′ of 12″ wide 4/4 hard maple and about 6′ of 6″ wide 4/4 soft curly maple. In my mind’s eye I see the ply wood used for the mount, the LTA, and the UTA rings; the hard maple, for the altitude trunnions; and the curly maple to connect and support the UTA. Remainder from the hard maple board could be used to hold the trusses. I also got four six-foot, 1.24″ dia, pine dowels for the trusses.