TITLE: 07/10 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 137Mpc
SHIFT SUMMARY:

IFO is in NLN and OBSERVING. Locking was tough to achieve today. As reported during the midshift update, initial alignment just couldn't work and as such, we skipped it when manually aligning its failing parts (MICH and SRC) and normal locking went smoothly. DRMI was initially acquired without resistance but then lock was lost thereafter. On the second trial, PRMI had to be locked first but then DRMI locked easily. We paused briefly at Engage DRMI ASC in order to ensure that the RF18 and RF90 lines were stable. At this stage, I touched the beamsplitter ever so slightly in order to bring the beams to a circular shape on the AS_AIR cameras. Locking went smoothly until OMC_Whitening, which took the longest time to progress from due to terrible violin modes (this week's culprit I'm told). While waiting, learned that sometimes, guardian might change the gain values for the violin mode filter banks but then not change them back, resulting in slower progress. After learning from Camilla and Austin, I bypassed this by changing all the gain values to their nominal values (slowly and incrementally). This still took a while, but finally, NLN OBSERVING was reached at 5:28 UTC.

Other:

- I tweaked the SQZ OPO Temp per Vicky's request during the long OMC Whitening phase. The values of the temperature were changed to maximize the green trace as per step 3 of the instructions in alog 70050. Both screenshots demonstrate the change in the green trace. The first (1) is right after the change and the second (2) is while in NLN Observing. The overall improvement was from ~0.0658 to 0.0666. The SDF difference this temperature change induced was accepted in order to move to observing.

- Since the mid-shift update, Daniel has posted more details concerning the potential issues with initial alignment. We did NOT fix it and this issue will likely occur in the future as this is the third time in a row MICH failed to lock during initial alignment and not even the first time this step was skipped. Work will lilkely need to be done this week to see what this issue is.

- Ryan C had a similar issue during initial alignment with locking SRC where he could not get the differential to be remotely near a delta of 5 (highest I could get is 3.5) in the "high highs and low lows" value for H1:ASC-AS_A_DC_NSUM_OUT16*0.001. He also just bypassed the issue by moving to normal locking, where it worked. This is documented in alog 71026. Again, that issue was not fixed.

- Rahul will be working on violin modes remotely from India (and will be in communication with Ryan C, the next operator).

- Special thanks to Camilla, Austin and Daniel who worked with me (and I, them) to get this thing locked!

LOG: