[Commissioners]

As yet another thing to try alignment-wise, I moved the IMC's uncontrolled alignment degree of freedom.  

In the attached plot, the y-axis references are set from our Nov 16th, 2025 15:32:00 UTC reference time.  During this time today PRX was locked, so the absolute values on the ASC POP QPDs aren't really comparable to the reference time, but since there was no PRX ASC, there should still be changes on the POP QPDs. 

I moved MC1 (top left traces in attachment) temporarily to the top mass osem position from Nov 16th while IMC ASC DoFs 1,2,3 were all closed (with a little higher than normal gain) and indeed see that MC3 responds in the expected way for the uncontrolled DoF.  For a reminder on the uncontrolled degree of freedom, I'm looking at Jeff's G1301131 page 23. I expect the sign of the yaw on MC3 to be the same as the sign on MC1 (and it is), and I expect the sign of the pitch motion on MC3 to be opposite of that of MC1 (and it is).  So, I think that indeed I've moved the uncontrolled DoF (called DOF4 in that slide deck).  

When the uncontrolled degree of freedom is moved, I'd expect the pointing of the beam coming out of the IMC to change (I have not calculated by how much).  In the attachment, I see that IM4 trans indeed looks like it has moved by about 0.04 normalized counts.  I don't see much change on POP A or POP B QPDs - if there's any change, it's extremely small.  

Anyhow, I'm not sure there's anything deep here, but perhaps we could go back to this MC1 position from Nov 2025 and then move IM3 to get back to the reference position on IM4 trans and then move IM4 to get back to the reference position on POP QPDs, and see if that changes anything.  We've moved more than this on the IM4 and POP QPDs already over the last few days, so I'm not sure that doing so will magically fix things.