The Upper Section
The upper section construction actually first required that the 12 foot "outriggers" at the North end of the building be constructed and supported. The outriggers were 4x4s with two more 4x4 posts sunk into the ground and concreted into place. A cross-brace was added later.
The upper section, like the lower one, was framed with 4x4s with wall studs being 2x6s. The East and West side 4x4s ride on six four-inch casters, guided by 20 foot pieces of channel iron. The six castors per side for such a relatively small building are, I believe, the primary reason that the upper section slides so easily in spite of the significant weight of the upper section. (That, and lots of silicon spray, liberally and regularly applied.)
Two reasons the upper section weigh more than what one might expect from a ten-by-eight wall/roof of this size is because first, I used a LOT of 4x4s and 2x6s, and second, because of the lumber, including the wall studs and trusses, was made from treated lumber. (Loooong story as to why I used treated lumber. Suffice to say that if you were to duplicate this building, you would no doubt be able to do so without treated lumber and save yourself a LOT of weight!!)
The roof trusses are shown here before their ends were cut. Also, the 4x4 bracing for around the door, can be seen. They were firmly lag bolted together and into place.
This view is meant to show in slightly better detail, how the upper section of the door was framed, out of 4x4s. There is no noticible flexure or weakness around this opening, usually the weakest part of this type of roll-off roof/ split door design. The 4x4 framing was lag bolted together, and was then bolted to the outside 4x4s. LOTS of bolts!!
Total height of the upper section walls is only slightly more than eighteen inches. This allows the upper section to clear the 10" LX-200 with lots of room to spare. I could easily mount a piggyback scope on it, or even replace it with up to a 16" scope and the door frame would still easily clear, I'm sure.