We're really struggling to acquire DRMI lock. It looks like our aux length loops suddenly have way more noise than they did before our last long lock stretch.  We're not at all sure why this is, but may want to look into it more, in case it hints at why we have more noise in the aux loops now than we did before we did the grouting / realignment in April. We can lock PRMI, but it is very noisy, and if we try to improve the buildups the noise gets worse.

We had a nice long lock, but then struggled to relock.  Nutsinee did an initial alignment, during which we decided to move IM2 and IM3 closer to their nominal positions, in acknowledgement of the warnings that have been on DiagMain lately.  However, we still couldn't aquire lock, so started to look at the noise.

Sheila and I found a time from earlier today (17Oct2016 16:03:00 UTC) where we were locked on PRMI for a few minutes, and saw that the MICH and PRCL noise was quite good.  In the attached screenshot that time is labeled "10+ hours ago".  When we first caught the PRMI, we had noise that looked like the "really bad" time in the screenshot.  This is more than 2 orders of magnitude worse than the quiet time for MICH between 10Hz-200Hz.  For PRCL the noise is only worse below about 150Hz, but it is still egregious.  By moving the alignment of the recycling cavity mirrors and the input steering mirrors, we could reduce the noise to the third set of traces, at the cost of losing at least a third or so of our sideband buildup. 

Thinking that this could be somehow related to our restoration of the IM2 and IM3 positions, we restored all suspensions (except RMs and OMs) to their witness or oplev values from 14 hours ago.  Patrick then did a careful initial alignment, but unfortunately our noise is still the same.  We can acquire PRMI but not DRMI.  At this point we're going to leave things as-is for now, and look into it again tomorrow after maintenence. 

We wonder though if this is a clue as to how / why we have so much extra noise in our aux length loops since April.