Hang, Dan
Last night after the lockloss we initially had some issues with the fast shutter not passing the test. Checking this morning this was because the AS beam was misaligned and there wasn't any light on the QPDs to do the test with.
The cause was SR3 pitch, looking at the oplevs and OSEMS it dropped after the lockloss and never came back... Adjusting the sliders values by 15 puts us back at the previous oplev/osem value. SR3 usually gets a kick during a lockloss however it always comes back. The fact it didn't this time seems odd.
This morning we have been trying to get the interferometer aligned, green arms lock fine but when we try initial alignment DOFs 1, 2, and 3, diverge way more than usual at the start and then won't converge.
We temporarily commented the fast shutter check in PREP_FOR_LOCKING so that it continues with setting up the suspensions. Otherwise the beam is clipped through the OFI and the power is not high enough for the fast shutter to complete it's check. This should be moved to some later stage perhaps, however we don't know what would be appropriate so we'll leave this fix to someone who does.
Even after completeing initial alignment and then adding the fast shutter check back into PREP_FOR_LOCKING it won't pass the test. The levels of light it is looking for on AS B and A are between 2500-6000. At this stage on single bounce we only see about 1000 and 5000 with 10W SRY, so we're not sure how this is using such high levels for checking the shutter works.
During ENGAGE_ASC_FOR_FULL_IFO and the dither loops are converging SRC1/2 struggles to keep up in yaw and we lost lock a few times. We manually helped it along until everything converged nicely.
We also wanted to update the initial alignment references as we found last night and today that the two positions are significantly off in yaw. While the arm was locked and converged we open the green shutters and moved the green QPDs offsets to zero the WFS signals and then updated the initial alignment green camera references,