A few construction pictures
The 4000 lbs of hand-mixed concrete for the pier, inside the form. The cage to attach the 100lb metal telescope pier is embedded in the concrete, with the bolt heads from the 2' concrete sticking above the surface, visible along with the template to point align the pier to the north (wooden). I had a back-hoe that was working on the septic in the front of my home, and had him dig the footers while he was at my home. All footers are 2'x2'x2', with eight 80 lb bags of concrete poured over gravel in each hole, allowed to cure, and the size 6x6" posts sit on these footers. I used sonotubes to back fill concrete around the posts above grade.
My son David helped to mix the concrete for the footers. I ended up filling my truck and trailer with 102 eighty pound bags of concrete, purchased from Lowes (their delivery schedule was full!). Took three separate trips, purchased as I mixed it, due to the weight.
Here are the completed floor joists, showing how they are fitted around the pier."
Advantec 3/4" flooring glued and screwed to joists, but leaving an air gap around the pier. This gap was then covered with wire mesh sold as gutter gaurd, stapled to the floor. This was followed with a layer of screen, and finally a carpet extended over the floor to pier gap. It is not visible but you can feel the joint if you probe with your toes.
And finally a shot showing my Dad, who came over many times to help frame the observatory, and provide good ideas ("Son - why are you doing it THAT way?").