With Keita's permission, I did a quick test of closing the pop beam diverter.  

Background:

We have been running with the POP beam diverter open, and saw in the past that there was a scattered light problem from ISCT1 (30835, the comment to this alog reports that the beam diverter would be automatically closed, but because of ASC problems we have actually been running with it open)  Since the range has been slowly deteriorating over the last few weeks, (see the trend of H1's range over most of O2 so far in attachment) I wondered if our alingment has drifted so that the scattering problem from ISCT1 is worse.  Keita agreed that it was worth a quick test.  

We closed the beam diverter at 22:24:25 UTC Jan 11 2016 and opened it again at 22:34:30 UTC.  Based on the spectrum and range, this didn't have a big impact, so it seems like the POP path on ISCT1 is not the culprit for this range drop.   We are now back to observing with the normal configuration.