We should completely turn off the air conditioner when working on green locking.
Even if green beams propagates inside of chambers, the air conditioner does affect the spatial jitter of the beam.
The attached picture was taken when Steve and I were seeing how the green beam jittered.
At that time the beam was injected from the end table and going through inside of the ETM, the ITM and the BS camber.
Eventually it came out from the camber and hit the wall outside of the chamber. It was obvious, we could see the jittering when the air cond. was ON.