PSL power into JAC 200mW. Jennie was able to lock JAC without much problem.

Jenne put MC2 back to march 2026 (in-lock) alignment in PIT and YAW using osem (not the slider) taking into account ISI (HAM3) Rz. 

To see the fringes, we injected 600 counts 0.2Hz into H1:SUS-MC2_M1_DRIVEALIGN_L2L_EXC. IMC flashed right away but the transmisison fringe looked like a weak horizontal line. Moving MC2 alone did not make the fringe converge.

Jenne moved MC3 and MC2 (and MC3). Improved some but not drastic. Tried JM3, again improved, but not drastic. Jenne was able to see the MC2 TRANS SUM but it was awkward and slow. At this point, at least the beam was not a straight horizontal line any more, we saw HOMs both in PIT and YAW, sometimes even 10 and 01 and what might have been a dim 00 spot. According to Jenne, the maximum MC2_TRANS number observed (about 3 after subtracting DC offset with 200mW input) is about 10% of what we expect with a good alignment (300 counts with nominal 2W).

We need a better alignment to be able to see the beam in the ISS path, though, I couldn't see anything.

I wanted to see the PRM reflection on the ISCT1 REFL camera as it will make the alignment easier (because we can see the IMC transmission beam shape).

Inside ISCT1, the beam was making it to the BS for the 1F diode but was hitting the mirror holder of the mirror for the BBPD. I touched up the common steering mirror for 1F and BB (just downstream of the shutter) so the beam goes to the direction of BBPD (and of course 1F PD) but could not see the transmission of the mirror for the BBPD using a card and a viewer, probably because the power was too small. (We're injecting 200mW, MC2 transmission is a small fraction of that as of now, and the REFL path is supposed to handle 60W.) No beam was seen on the camera either.

On Monday we might temporarilly move the BS for the BBPD out of the way so we can see the beam on the camera.