J. Kissel, E. Merilh, C. Vorvick

Below is a summary of what Cheryl led us through today:

 - PRM and PR2 Irises placed in-vacuum
 - Performed daily alignment of IMC by adjusting PSL PZT, and IMC Mirrors
 - IMC flashing speed reduced by turning down HAM2/HAM3 purge air
 - IMC alignment fine-tuned by driving MC2 broadband in L from 0.2 to 0.25 Hz (to have RMS velocity dominated by a slower pulse than the 12 Hz HEPI pier resonance noise)
 - IM1&2 alignment finalized (via sliders / actuators) using IR card views of flashing beam at Faraday Isolator input and output apertures 
 - Flashing beam routed through to PR2, but found that IM3 needs entire DAC range in Yaw (consistent with what was seen during first observing runs)
 - IM3 alignment mechanically offloaded in Yaw using OSEM sensors
 - Re-tightened all IM3 cage / structure bolts

A video of the flashing can be seen here: https://youtu.be/8DJnQ45cmK0. The speed at which the IMC is flashing through alignment fringes is reflective of the 12 Hz pier resonances transmitted through the locked HEPI and ISIs in HAM2 / HAM3 (see LHO aLOG 39328).

Attached are screenshots of:

 - The evolution of alignment sliders during the daily re-alignment of the IMC in Pitch and Yaw
 - Screenshots of OSEM positions and alignment sliders after we finalized the IMC alignment 
 - Screenshots of OSEM positions and alignment sliders after we finished alignment of IM1 and IM2, and after mechanically offloading IM3

We ran out of time today given the extra work with IM3, but we will resume tomorrow morning around ~10a, with the end-goal to install the IMC bypass and hand off to further down-stream alignment of the IFO.

Any work that needs laser safe will be free to work laser glasses free for a few hours in the early morning.