Last Friday and this morning, with Bruno, we close the ring/cavity valves and put some dry air in the two vessels through a filter to avoid turbulences.

Now, the two vessels are at ambient pressure and ready for opening (to remove the mirrors).

One can let the ambient pressure in the vessels as long as we want, the ring/cavity valves have been chosen to be compatible with the high vacuum in the ring and the ambient pressure in the vessel for a long time.