Changes made to the IMs today:

• all alignment offsets set to zero(0)
• all alignment offsets saved in SDF
• all LOCK FILTERS filter outputs turned off on all IMs (IM4's were already off, so no change for IM4)

Current OSEM centering:

• IM1 has had it's OSEMs recentered
• still to center: IM2, IM3, and IM4

Alignment offsets on IM3 and IM4 pitch that were necessary for the first alignment to PR2 are better understood:

• IM4 pitch OSEM readback shows -4051urad with a zero alignment slider value
• IM4 pitch when the beam was aligned within a few mm of center on the PR2 iris was -2720urad
• the difference is 1331urad
• at PR2, a distance of 16.7m (approx. dist from IM4 to PR2, ignoring PRM), the IM4 pitch angle change of 1331urad shifts the beam by 22mm
• all other IM pitch OSEM values are less than 100urad from zero with a zero alignment offset
• this suggests that the current IM4 pitch value of -4051urad is pointing the optic around 67mm high at PR2
• this also suggests that IM4's pitch at zero alignment offset will need to be adjusted
• further diagnosis will require the beam from the PSL