H1 Manager woke me up complaining about having been out of Observing for over 10 minutes. I checked and found that the issue was that the OPO ISS was not able to stay locked. I took the detector to NO_SQZING, took the OPO guardian to LOCKED_CLF_DUAL_NO_ISS and noted that OPO trans was around 62 uW, much lower than our 80 uW setpoint, so I used 86767 as a checklist of what to do, since we had had the same issue a few weeks ago.

I checked the SHG temp (it had been updated earlier today (87233), and it was still looking good and above 90mW, so I went to the next step from that alog - adjusting the half wave plate that's in the SHG path between the 200 MHz AOM and the SHG Rejected Power PD. I had an ndscope open with H1:SQZ-OPO_TRANS_LF_OUTPUT and H1:SQZ-SHG_LAUNCH_DC_POWERMON, and adjusted the wave plate a step at a time until the SHG launch power was about/above what it had been before (~26uW), and OPO trans was above the 80 uW setpoint. Once that was done, I was able to relock and reinject squeezing with no issues and went back into Observing.