While Arrow sheds are great conversion "kits" for rolloff roof observatories, they are very flimsy in the initial stages of building. Arrow tells you to start and finish on a calm day. Here in my part of Indiana, it's rare to have no breeze at all and on the hilltop chosen for the observatory, there's a stiff breeze all the time. My son-in-law Nathan and I started the walls the morning. It was very breezy, but we found a good solution, as the pic below shows:
We used chairs to brace the panels inside and outside (they were tightly sandwiched). Without the chairs, the walls, which are about a tenth of an inch thick, would have whipped around and been destroyed. Some people have had significant problems building these sheds (mostly misaligned holes and problematic panels). We paid particular attention to the instructions that came with the shed that said the base had to be level and square and we had very few issues. Arrow tells you not to anchor the building or put the floor frame in until the building is complete. We did both because the corner gussets of the anchor set and the floor frame helped to keep everything square. In addition, if the building had not been anchored, it would have blown away! It is a lot easier to work on an anchored structure!
Arrow also tells you to raise the four corner panels before you put in the bracing. We broke this rule, too, and braced each wall as we completed it (the rear wall is braced above). The bracing really helped to steady the walls as we continued building. Within an hour, the observatory looked like this:
The upper and lower braces are in place and the structure felt remarkably sturdy. We removed the chairs and continued to build.
With the door frame up, and all the walls screwed on, the building seems very solid. Here's a view of the inside:
This shot shows the interior walls and bracing, plus the floor kit and vapor barrier. There's no hole for a pier, as the scope will stay on its tripod.
In the next phase of building, we'll build a timber frame of 4x4s that will sit on top of the walls. I need 4x4s as the 14 is a big scope, and the roof will not clear the scope as it rolls off unless the walls are at least 65" high (the walls without the 4x4s are 62"). This frame will be supported by 4x4s in each corner--BUT, that presents a problem--which I'll talk about in the next update.