I started to repeat the measurement described in llo alog 28797 while we were waiting for LLO to come back up around 20:05 UTC. Since LLO is back, I have stopped and put things back to normal, and Cheryl is running A2L before we go back to observing. (This was about 45 minutes of commisioning). 

I got as far as tuning an excitation and finding that an offset of around 0.3 in POSY may be about right, but that we need to wait a long time for the OMC ASC loops and the slow kappa C calculation to settle when making these measurements.  The template with the excitation is saved at sheila.dwyer/OMC/OMC_alignment_jitter_check.xml  We will continue this Wednesday.

Starting CP3 fill. LLCV enabled. LLCV set to manual control. LLCV set to 50% open. Fill completed in 1200 seconds. LLCV set back to 20.0% open.
Starting CP4 fill. LLCV enabled. LLCV set to manual control. LLCV set to 70% open. Fill completed in 1484 seconds. LLCV set back to 38.0% open.

RickS, VaishaliA, HeatherF, SudarshanK

We analyzed the pictures of the ETM and Pcal beam spots taken on 2017/04/11 (Tuesday maintenance) to determine the position of the Pcal beams. The numbers below are the position of the Pcal beams from their nominal position of [ 0, 111.6] mm for upper beam and  [0, -111.6] mm for lower beam. 

Upper Beam [1.1+/-0.3, 1.1+/-0.2]

Lower Beam [-1.1+/-0.2, 1.3+/-0.3]

These numbers are comparable to numbers obtained from the pictures taken few weeks ago - LHO alog # 35347.

P.S. The number reported here are mean values of multiple analysis on multiple pictures  and the number in the attached picture is only one such number and thus may be different.

I don't see any egregious excursions.  The brief dip in the EX pressure was previously noted in TJ's trend from March 20 (aLog 34936).  Also, the glitching in the EY pressure noted in the same aLog seems to have been fixed.  This closes FAMIS task 4531.

TITLE: 04/17 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 64Mpc
OUTGOING OPERATOR: Ed
CURRENT ENVIRONMENT:
    Wind: 9mph Gusts, 7mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY:

• locked 34:41 hours:minutes
• range took a dip about 3 hours ago and recovered, but
• range is currently trending downward a bit

TITLE: 04/17 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 55Mpc
INCOMING OPERATOR: Cheryl
SHIFT SUMMARY:

Nothing to report. IFO locked for 34hrs20min
LOG:

7:28UTC YAW out by .65

7:33UTC Intention Bit Undisturbed

TITLE: 04/17 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 63Mpc
OUTGOING OPERATOR: Corey
CURRENT ENVIRONMENT:
    Wind: 14mph Gusts, 12mph 5min avg
    Primary useism: 0.06 μm/s
    Secondary useism: 0.12 μm/s
QUICK SUMMARY:

TITLE: 04/16 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 64Mpc
INCOMING OPERATOR: Ed
SHIFT SUMMARY:

H1 locked for over 26hrs.  Fairly quiet other than an earthquake (which we rode through).
LOG:

• 2:29:  "incoming earthquake" Verbal Alarm, Terramon only marks it as 0.407um/s & it was due to arrive 30min earlier.
• 5:46:  Road through 5.6 magnitude Barbadu Earthquake 

Didn't really notice this until I happened to look up at the Pit ASC Control Signal strip tool and saw noticeable oscillations, & then I saw all other markers for an EQ.

• EQ seen at: 
  • USGS: Listed as occurring at 5:23utc
  • Seis BLRMS:  ~5:46utc (peaked at 0.6um/s for 0.03-0.1Hz)
  • Terramon:  Not sure when this posted, but it gives arrival time of 5:52utc
  • Tidal signals oscillating from ~5:53 - 6:21 utc
  • Verbal Alarm did not announce anything
• Magnitude: 5.6
• Location: Barbuda (Carribbean)
• Start time: ~5:46utc
• Lock Status: Observed on H1 Tidal signals; BNS range did not take any hit; H1 remained locked.  L1 Lost lock.

A2L measurement showed elevated in Yaw, so ran A2L.

4.7kHz was damped at the beginning of the lock last night with 0deg (MODE10 outmon went down to +/-2000counts on strip tool).  But saw that the resonance was rung up again.  So, I tried +30deg & this quickly rung up the resonance.  I then added -60deg (for net -30deg) & this took damped out the resonance within minutes (& took the MODE10 outmon to +/-10 counts).

Summary of 10min out of Observing:

• 0:30utc  L1 Down, dropped out of OBSERVING
  • 0:30 - 0:38 Ran A2L (because was out in yaw)
  • 0:38 - 0:41 Damped 4.7kHz resonance by ENABLING FM9 [+30deg] (which rung up within seconds) & then ALSO ENABLING FM6 [-60deg] which damped out in within a couple minutes.
• 0:40 H1 Back to OBSERVING

TITLE: 04/16 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 64Mpc
OUTGOING OPERATOR: Cheryl
CURRENT ENVIRONMENT:
    Wind: 7mph Gusts, 5mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.12 μm/s 
QUICK SUMMARY:

• Lock is currently going on 19hrs.  
• Winds are under 10mph.  
• Notice the 4.7kHz resonance is back.  At the beginning of this lock last night, I had turned OFF the FM9 (+30deg) to bring it down.  It looks like it's come back during the lock.

TITLE: 04/16 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 62Mpc
INCOMING OPERATOR: Corey
SHIFT SUMMARY: locked all shift, no issues other than some wind causing some noise, web page stat was yellow is now green

I have just restarted the primary and redundant pipelines at LHO at GPS time 1176395700. Due to an issue with the computed kappas being out of the expected range, h(t) was marked bad by the calib_state_vector. This is due to a bug in the most recent release of the calibration code, gstlal-calibration-1.1.5-v1. For more information on this bug and the proposed fix, see https://bugs.ligo.org/redmine/issues/5494

TITLE: 04/16 Owl Shift: 07:00-15:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 64Mpc
INCOMING OPERATOR: Cheryl
SHIFT SUMMARY:
LOG:
Quiet night again. Apparently, something happened with h(t) last night at 3:11 local (?), got a call from UWM about it. Sounds like they are looking into it.

TITLE: 04/15 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 65Mpc
INCOMING OPERATOR: Jim
SHIFT SUMMARY:

One lockloss through the night (~30min down).  

Had a couple of SDF diffs:  

• To get rid of the ECAT ALS ones, for ALSX I made a change to it's request from Red Locked to End Locked.  But I'm thinking this might have been Accepted in a wrong state (ALSy is in the Red Locked state & perhaps ALSX should be accepted that way).
• LSC & IMC REFL_SERVOs were off by 1-2dB---this is due to the low PSL Power.

There were number of high frequency calibration lines injected using the automated Guardian scripts. These lines are injected using the Pcal at ENDX (ENDY is used for calibration purpose). The GPS time at which these lines were running are listed below:

I have added an (unreleased) algorithm into the GDS/DCS pipeline to compute the SRC spring frequency and Q. This algorithm was used to collect 18 hours of data on February 4 (first plot) and 18 hours of data on March 4 (second plot). The plots include kappa_c, the cavity pole, the SRC spring frequency, the SRC Q, and 4 of the coherence uncertainties (uncertainty of the 7.93 Hz line is not yet available).

The derivation this algorithm was based on is similar to what Jeff has posted ( https://dcc.ligo.org/DocDB/0140/T1700106/001/T1700106-v1.pdf ), with differences noted below:
1) The approximation made at the bottom of p4 and top of p5 was only used in the calculation of kappa_c and the cavity pole. So SRC detuning effects were not accounted for in computing S_c. However, kappa_c and the computed cavity pole were used in the calculation of S_s.
2) In eq. 18, I have a minus (-) sign instead of a plus (+) sign before EP6. S_c = S(f_1, t) has been computed this way in GDS/DCS since the start of O2 (I assume during O1 as well).
3) Similarly, in eq. 20, I have a minus sign (-) before EP12.
4) In the lower two equations of 13, I have the terms under the square root subtracted in the opposite order, as suggested by Shivaraj. (Also, I noted that the expression for Q should only depend on S(f_2, t), with no dependence on S(f_1, t). )

The smoothing (128s running median + 10s average) was done on f_s and 1/Q, since that is the way they would be applied to h(t). Therefore, the zero-crossings of 1/Q show up as asymptotes in the plot of Q. I think it would be better to output 1/Q in a channel rather than Q for this reason.

There is a noticeable ramping up of f_s at the beginning of lock stretches, and the range of values agrees with what has been measured previously.

I've noted that it is quite difficult to resolve the value of Q with good accuracy. These are some reasons I suspect:
1) Higher uncertainty of calibration measurements at low frequency can add a systematic error to the EPICS values computed at 7.93 Hz. This may be why the Q is more often negative than positive ??
2) In the calculation of S_s, the actuation strength is subtracted from the ratio of pcal and DARM_ERR. Since this is such a low frequency, the subtracted values are close to the same value in magnitude and phase. Thus, subtracting magnifies both systematic error and uncertainty.
3) The imaginary part of S_s (see eq. 13, bottom equation) in the denominator, is very close to zero, so small fluctuations (about zero, as it turns out) in 1/Q cause large fluctuations in Q.

These reasons make it difficult to measure Q with this method. The effect of these measured-Q fluctuations on S_s, the factor we would actually apply to h(t) (see eq. 22), is not enormous, so long as we apply the smoothing to 1/Q, as I have done here.