TITLE: 07/20 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 145Mpc
SHIFT SUMMARY:

- Started off the shift with a lockloss - cause unknown

- Reacquisition was automated, but we lost lock at TRANSITION FROM ETMX, EY/IX saturation

• Following reacquisition was unaided, waited at OMC WHITENING to damp violins

- Acquired NLN/OBSERVE @ 2:05

- I took a spectra of the 2nd harmonic violin modes - a current theory as to why the violins are ringing up is due to the 2nd order harmonics coupling into the first and fundamental modes, scope attached - Tagging SUS

• A quick look at the spectra shows that between 1460-1510 Hz (and to a lesser extent 1930-1980 Hz), the 2nd order modes do look particularly bad
• Perhaps we can try to mitigate these modes by creating monitor and damping filters, find their respective damping settings, and see if this helps to resolve our ongoing violin issue

- Note: The new H1 manager node we are testing automatically sets the requested state to be NLN, however due to the violin issue we have to wait in OMC WHITENING

• A temporary workaround for this is to wait until ISC LOCK has reached MAX POWER or higher when relocking, then request ISC LOCK to be unmanaged, wait at OMC WHITENING to damp, then remanage again once back to NLN - Tagging OpsInfo

- Leaving H1 to Ryan C. with the IFO locked and in observing for just under 5 hours

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