Danny, Georgia, Sheila, Hang, TVo

After fixing the mask today, the HWS ITMY shows that the clipping issue we've had before is now fixed and the heating profile is more circularly symmetric.

We still got a contrast defect of about 0.4%, but we didn't optimize the differential CO2 power because we saw an obvious pringle mode (HG20-HG02) that stems from astigmatism,  this shows up pretty obviously when looking at the single bounce beams where ITMX looks good, but ITMY looks bad.  

Sheila suggested that we should be able to scan the PR3 around the ITMY surface and see the astigmatism in the single bounce ITMY beam vary as we start to sweep over the center of the CO2 lensing.  This worked a bit but we started clipping after moving the spot position on ITMY by about 5 mm so it gave use a direction to try to aim for when changing the alignment of the CO2 beam relative to the test mass. 

Although this had confusing results because we once tried pico-ing to where we thought it should get better by doing a modulation of the laser power and seeing the deflection at the anti-symmetric port with the ASAIR camera, the astigmatism didn't seem to get better.  Changing the picoing in the y-direction showed that the deflection went up whether or not we pico-ed up or down in counts so we thought we might be at a minimum, however, If we went through a minimum then we should see a phase change between the heating cycle and the deflection slope but we weren't able to observe this which makes it even more confusing.

In the end, there was still astigmatism after the pico-ing but Sheila suggested that the morning commissioning crew try to lock and see how these particular lenses change our locking scheme/setpoints