Lisa

At Livingston they have to realign the arms very frequently in order to mantain high power build up. It seemed like we were not seeing the same problem here, but we didn't really have any numbers for Valera.

So, I left both arms locked on green last night. The plot shows a 6 hours trend of the green transmission power for both arms, and amplitudes of the beat notes. The guardian was left on, and it was automatically recovering lock.

The Y arm power dropped by ~10-15% over 6 hours. For whatever reason X was drifting much more than Y. Still, on a 1 hour timescale, you can't really see any significant drift; over 6 hours, the X arm drift was ~50%. I don't know if it has been already observed in the past that X drifts more than Y, or if it was just an isolated event.