I’ve done a rough calculation of the expected pitch/yaw from PR3/SR3 to ETMx/ETMy ACB PDs 1 and 4. Results come out the same, only differing in direction depending on which PD we’re shooting for. One big assumption I made: aligned PR3/SR3 points to center of ACB (not sure if this is true in practice). This is to aid in our attempt at refining PR3/SR3 OpLev pitch/yaw calibrations after Sheila noticed discrepancies here.