Dome Construction Since commercially-made domes are extremely expensive, even those made for amateur observatories, I decided to design and build my own dome. I planned on purchasing the materials (aluminum sheet and structural shapes) and doing all the construction work myself to cut costs. (The only work to be done by metal-working companies is rolling some pieces into arcs.) That leaves me with lots of calculating, cutting, welding, riveting, and fastening to do! At the time that I ordered the materials for the dome (November 2001), aluminum prices had risen very high, but it was still cost effective to build the dome myself rather than purchase one. The most critical and structurally important part of the dome was the set of two base rings. One would fasten to (and be supported by) the wall framing of the building and the other would form the bottom-most piece of the dome itself. Three sets of roller blade wheels between the rings would allow the dome to rotate like a giant bearing: one set would support the weight of the dome and would allow rotation, another would keep the dome centered over the bottom ring, and the third would hold the dome down to the building without imparing the rotation. The dome ring would be slightly larger and overlap the bottom ring when meshed together to keep precipitation from getting in between the dome and building. The two rings would be made from 3/8" thick 6061 aluminum angle, the larger being 4" x 4" and the smaller 3" x 3". The necessary diameters are 122" (10'2") and 120" (10'), respectively. For storage and transportation purposes, it was decided to have two hemicircular arcs made for each ring until we were ready to put the whole thing together. (The arcs will have to be TIG welded together.) Special arrangements had to be made to get these pieces rolled into 60" and 61" radius arcs and by late November 2001, we were finally able to pick up almost all the dome materials. In December, we picked up the dome sheeting and in January, the tee stock that will form the ribs of the dome was rolled into arcs by a Chicago company. At the end of January, all the materials were ready for assembly, but will have to wait until spring when the weather is better. Click to enlarge: John and Julie Posing with the Dome Arcs Dome Materials Ready for Transport