This page documents the original build of the rotating roof observatory

No construction is complete without a foundation of course...


So the construction started with the building of the foundations. A large concrete plinth, 1m x 1m, was cast to stand the telescope on. The central hole in the plinth allows electricity and data cables up to the centre of the observatory.

The paving slabs were concreted into place and they support the floor frame which was constructed from 80mm x 40mm pre-treated timber. The right hand area was divided to use as an underfloor junction box for the electricity.

The floor was completed with tongue and groove floorboards and painted with exterior wood stain/preservative. A cover was made for the junction box for access from inside and the electricity cable is now in place.
The walls for the lower (stationary) base of the observatory are made from 8 identical frames bolted together and to the floor/base. Each frame was clad in shiplap except for the wall that was to eventually take the door.
The top of the base walls was the place to put the dome rotation mechanism. This consists of two identical sized steel rings (2.4 metres diameter). The top ring has 8 grooved castors and runs on the lower ring like a train on a railway.
This shows a detail view of one of the castors. The lower ring is bolted to the lower walls of the observatory and the rotating dome is bolted to the top ring. The rotating mechanism works like a dream.
The dome walls were constructed from 7 identical frames (leaving a gap for the slit) clad in shiplap. These rested on a circle of plywood which will eventually be fitted with a skirt to close the gap between the base and the dome.
The roof timbers were put in place leaving a clear area where the dome slit was eventually going to be.
The roof was clad in plywood which would eventually be felted. It is now really beginning to look like an observatory!.
Here the skirt has been fitted around the dome. This is made of hardboard covered with aluminium coated bitumen flashing (the type used for patching holes in flat roofs). I’ve also fitted the door at this stage.
More or less at the finishing stages. The roof has been felted and two timber framed shutters have been made and fitted to the dome.
The shutters slide apart to open the slit. Each shutter is fitted with a drawer slide from a filing cabinet at the front and the back. The shutters then operate like a filing cabinet drawer and slide aside easily.
This detail shows the shutter latches and some of the weatherproofing added to keep the rain out.
And finally in early 2002 the 8.5 inch telescope was moved from the run off roof shed into it’s new home.