During the pandemic confinement, I took the opportunity to undertake a major renovation of the dome. The improvements I had to take on were:
Replace the support base of the rotating part that had initially been built with wood. Although it was marine plywood, it had not withstood the weather well and had deteriorated quite a bit.
Raise the dome by 60 cm, in order to make it more comfortable to work inside and to improve the visibility on the horizon by saving some nearby buildings.
Improve the rotation system, which was originally designed by friction and although it worked properly, it required a lot of maintenance.
The main challenge was to raise the dome. Although the dome is not very heavy and can be handled by several people, a system had to be devised that would allow the dome to be raised, the fixed masonry part lifted and then lowered again. The solution was to fabricate two small scaffolds with a square steel tube profile to be placed in opposite positions and to lift the dome with four small car jacks. This solution was manageable by a single person and provided space to place the bricks that allowed the whole thing to be raised.
I ordered the new support base in laser-cut stainless steel. An extraordinary result, easy to install and offering an optimal friction to the dome wheels.
When raising the dome, it was necessary to add a supplement to the column that supports the telescope mount.
The rotation system was completely replaced by a 20mm wide polyurethane (PU) synchronous belt type T10 (https://www.beltingonline.com) and the corresponding synchronous pulley. The main complication was to properly attach the belt to the dome with a highly adherent silicone. The synchronous belt system made it possible to replace the original very heavy and expensive motor with a much smaller and more economical motor. The rotation is now slower, but this only slows down a little the alignment time of dome and telescope between different astronomical targets.
The decoder system to control the position of the dome was also made with a much finer pitch synchronous belt placed in parallel with the synchronous belt in charge of the traction.
I also took the opportunity to refurbish the electrical panel, simplifying and integrating the uninterruptible power supply system.
The result is a new, more functional and comfortable dome, with a better view of the horizon, and a finer, low-maintenance rotation system.
The current equipment is a C11 tube on EQ8 mount.
This video shows the new dome in operation together with the small ClamShell dome.