Derek noticed (via the summary pages) that there seems to potentially be an occasional discrepancy between CALIB_STRAIN_NOLINES and CALIB_STRAIN_CLEAN.
The NonSENS subtraction should be off. The first attachment shows that indeed the noise estimate output by the front end NonSENS is zeros to the 1e-27 level (these are in the same strain units as GDS-CALIB, and I just didn't bother scrolling in more to see how 'zero' I can make the y-axis) during a time when the discrepancies are visible on the summary page.
A next step is likely to try to zoom in on the time axis of the spectrograms from the summary page to see when these things are happening, and see what other things might be changing around those times (eg, are those the beginning of Observe segments or going in/out of NLN_CAL_MEAS?). Since the output of the noise estimate from the front end is zeros, _NOLINES and _CLEAN *should* be identially the same.
I investigated this issue further by looking at the data for the NOLINES and CLEAN strain channel between 6 and 8 UTC. This time period contained multiple times where the summary pages indicated that NOLINES and CLEAN were not identical (see attached plot).
When directly comparing the data for these channels saved in the H1_HOFT_C00 frames, I find no differences between the two channels. The difference noted on the summary pages appears to be a summary page issue/bug, and not an issue with the strain data.
The earliest day these anamolous features appeared on the either the L1 or H1 summary pages is June 5, which is the same day as a summary page update that included changes to the strain channels.
