I have moved IM2 and IM3 closer to their O1 alignment values, as indicated by Cheryl's alog 29948. At the same time, I was walking the POP_A offsets to keep the jitter coupling low. I had an excitation from 310-350Hz on IM3 yaw, but the effect it had on DARM didn't really change during this series of moves. But, the other jitter/intensity peaks seem to have perhaps gotten a teeny bit better. More significantly, this set of moves improved the carrier recycling gain as well as the 45 MHz sideband buildup in the SRC.
IM2 and IM3 I only moved in yaw, however this made their pitch values also line up more closely with their O1 values. IM2's witness sensors read (P: 608, Y: -209) while IM3's witness sensors read (P: 1954, Y: -32). The POP_A offsets are currently (P: 0.39, Y: 0.47). This gives a carrier recycling gain of 30.5.
If the IFO is a struggle to lock tomorrow, trend the IM2 and IM3 witness sensors and put them back. I'm leaving them in their new spots for tonight.
I also ran a2l.
We should check in the morning if these IM2 and IM3 positions help get us away from the REFL PD clipping that Sheila has been looking into.
IFO left undisturbed starting 08:20:00 utc.
This lock lasted for 8+hrs. PI modes 17 and 25 rang up and kept increasing in their amplitudes until the lockloss.
Going to stay with changes to the IMs Jenne made (from Cheryl's suggestion) for getting back to an O1 alignment.
Operator NOTE: This will give us a list of a few WARNINGs on the Guardian DIAG_MAIN (if we are happy with where the IMs are, we'll want to update Guardian to ACCEPT this IM alignment).