Having finished the steel skeleton of the room I went back to the dome section and decided to make some more scaled models to determine the exact cut, size and angles of the ribs and cladding
These patterns proved an invaluable help in calculating the size and shape of the sections involved and the angle of curvature required. One has to remember that the two ‘sides’ of the dome do not meet in the middle of course. They are separated by a gap that is the viewing window and will therefore be covered by the front window hatch, the main sliding hatch and at the back by a fixed section that completes the hemisphere. So when making the model, the base is not a semicircle but as can be seen in the photos it falls short by half the distance of the intervening viewing gap.