As Jeff alluded to in his summary, Sheila posted an alog about Oplev damping back in April, but I stopped looking at oplevs since the offcenter ITMX & ETMX had been that way for over a week (i.e. they were not a new feature).

After looking into ASC Land, I returned to the oplevs after going through Sheila's alog and then also looking at Krishna's alog.  Summary of Oplev operations over the last couple of months:

• Stopped using Oplevs to Damp Pitch for ETMx, ITMx, & ITMy on 4/7/17.  (ETMy was already not being used & we haven't been damping Yaw for a while.)
• BS is damped briefly while locking, but then zeroed out before getting to Nominal Low Noise.

So with Oplevs not actively not controlling optics, I didn't focus on them.  However, we still use them for monitoring position of the optics.  And with that, I returned to checking them out after reading Krishna's alog about ITMy.  I took spectra of all (4) test masses (ref from last night's lock & from when we had trouble with H1 tonight).  Of all the test masses, ITMy appears to be much more noisy, and it all begins down at 0.44Hz (this is the same oscillation seen in the ASC signals previously alogged tonight).

Following Krishna's diagnosis, I looked at the BLRMS signals for the oplevs in the H1 Summary Pages & one can clearly see ITMy starting to clearly look unhealthy compared to other optics toward the end of Jeff's shift starting between 4:00 -5:00 utc (look at bands between 0.3 to 10Hz).  The behavior isn't like what Krishna saw (back then ITMy reached values of 1.0+ urad for short times & in this case ITMy is just under 0.1urad, but stays there for longer stretches). 

Since we don't use oplevs for damping, could the issue be noise  from the light of the ITMy oplev being seen by H1?  Or is there an ASC effect which is also being observed with the ITMy oplev?