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Entry  Mon Mar 11 14:10:05 2013, Jenne, Update, Environment, MC suspensions moved by this morning's earthquakes EQ.pngMC-SUS-kicked-EQ.png
    Reply  Mon Mar 11 15:52:46 2013, Jenne, Update, IOO, MC spots centered, WFS realigned MCspots_11Mar2013.png
    Reply  Mon Mar 11 17:18:00 2013, Manasa, Update, Environment, Earthquake: Suspensions tripped and MC realigned 
       Reply  Tue Mar 12 00:45:50 2013, Jenne, Update, IOO, MC weird again 
          Reply  Tue Mar 12 11:49:18 2013, Jenne, Update, IOO, MC weird again 
             Reply  Wed Mar 13 02:48:13 2013, Jenne, Update, IOO, MC all better 
Message ID: 8269     Entry time: Mon Mar 11 15:52:46 2013     In reply to: 8268
Author: Jenne 
Type: Update 
Category: IOO 
Subject: MC spots centered, WFS realigned 

Looking more into the MC, it appears that no spot centering was done after the power attenuation optics were removed (see elog 8142).  Since Manasa had changed the zig-zag steering after putting in the attenuation optics (elog 7843) the pointing was not correct for the nominal MC.  This is (likely) why Yuta and Manasa found some significant decentering.  If Manasa's tweaks when preparing for vent were primarily in yaw, then this is most definitely what happened.  A note, this is why we should change to inserting the attenuation optics before the PMC, but even so, one should adjust the angle of the PBS, NOT the zig zag optics, to get the input pointing back to the same place.  This is also why it is useful to ensure the attenuation optics do not block the PSL pointing QPD pickoff, so it is easier to adjust the PBS to get back to the original pointing.

In any case, I touched the last zig-zag mirror in yaw today (the top of the knob was moved away from me) to recenter the spots.

MCspots_11Mar2013.png

With the MC unlocked, I centered the WFS.  Now the MC is back to its normal working condition....WFS are on, autolocker is on, reflected DC power is low, etc., etc.

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