Yesterday I installed teh QPD on the table behind MC2, and observed teh signal on it.
The MC_leak is directed to it by a steering mirror.
I used the A2L_MC2 script to minimise teh pitch and yaw gains, and estimated teh spot position on teh MC2 using that.
This spot position was aligned to the center of teh QPD.
In the night while before taking measurements, I decided to turn off the Wavefront Sensor Servos, but just after that, the MC alignment went very bad, and I could not align it in the next 2 hours.
For some reason, the MC was really mad the whole day yesterday, and was getting misaligned again and again, even when the WFS feedback was on.
The table also had another IR laser in it, which I and Koji switched off.
I will continue measuring once we pump down again.
For now, I am analysing teh QPD circuit Transfer Function.