The first consideration with any observatory is the location. In my case I chose a position that afforded good views N & S, reasonable E but not W, which is blocked by the house. The best position would have been the centre of the garden, but this would not have been too popular with the rest of the family!
The ground was pegged out and checks were made by setting up the scope on a high tripod at night before starting the digging out.
The holes were dug as accurately as possible to avoid leveling and positioning problems later on. The main pier footing is approximately a 900 mm cube.
The central pier hole is surrounded by the footings for the eight pads which support the posts that will form the walls. The length of each side is about 1100 mm giving a dome diameter of just over 3000 mm
