Cheryl, Ed

Cheryl asked me to post these plots in the case that locking becomes dificult, especially in the "INPUT_ALIGN" and "FIND_IR" stages of aligning and locking. It seems that 3 days ago after a HAM2 ISI trip there was a 15µRadian shift in IM2 M1 pitch and ≈7 µRadian shift in IM1 M1 of the same. The plot also shows the compensation that IM4 has made which ultimately affects the beam pointing/alignment for the entire IFO. Should re-locking become difficult or not stable it's possible that IM1 and IM2 may need to be driven back to the values from when the shifts took place. How much shift is too much shift is still being discussed.

Please feel welcomed to correct any inaccuracies in this log as I'm relaying information from Cheryl who's knowledge of this exceeds mine, i believe.