Control room crew including Keita Patrick Sheila Jenne Robert

As Betsy pointed out last night, the top mass osems in the corner station show that things have been sagging recently. The first screenshot attached is a 300 day trend of the same top mass osems that Betsy plotted.  

Patrick noticed that twice this morning when we lost lock, ITMY had a large alignment shift, although none of the control signals going to the suspension changed. (PDF attached) This probably explains why operators had to keep repeating initial alingment yesterday. 

Keita suggested that we look at the top mass osem spectra with no damping on, and indeed the spectra of ITMY are different from the other quads, which can be seen in the third attachment. We then added an offset to the top mass vertical osem, which moved it up by about 20 um (so that the top mass osem is back near 50um where it was in December).  The after the move the undamped spectra are much more similar to the other quads (third attachment shows the comparison to ETMY of ITMY with and without the offset, for V only, 4th png shows all DOFs)

We are now proceeding with inital alingment one more time, and will attempt to lock.  

The times are: all 4 quads undamped at 21:24:04 UTC Jan 16th 2017 to 21:43:00.  Offset added to ITMY vertical at 21:47:15 UTC.