H1 is back to observing at 140Mpc as of 03:10 UTC.

The biggest struggle with lock acquisition following the challenges of the day came at the DRMI locking steps. The POP18 and POP90 flashes have been consistently low recently, so ISC_LOCK went through PRMI to start, which was successful, but PRMI ASC wan't able to make the signal much better. When moving on to try and lock DRMI, I paused ISC_LOCK to give myself time to try a few things. After a while of adjusting triggering thresholds and LSC servo gains, the settings that finally worked to keep DRMI locked enough for me to adjust alignment and engage DRMI ASC were:

• LSC-MICH2_GAIN: 1.0
• LSC-PRCL2_GAIN: 1.2
• LSC-SRCL2_GAIN: 1.4
• MICH_TRIG (upper): 25.0
• SRCL_TRIG (upper): 25.0

After DRMI ASC was engaged and offloaded, I continued locking by resuming ISC_LOCK. I also set the LSC servo gains back to their nominal value of 1.0. The rest of lock acquisition went smoothly and unaided.

That said, BNS range is still on the low side and Camilla pointed out that the low frequency noise she noted in alog 74473 is back. Also, the secondary microseism is well above the 95th percentile and still rising, so things are unstable.