We attempted to center the beam on the HAM2 ISS array PDs using the steering picomotors; we set the IMC at 50W for this. We started with HAM2 picomotor 8, which is upstream of the ISS diode array telescope. The PD 1-4 signals were centered at maxima when the beam on the ISS array QPD was centered (BTW, as Cheryl pointed out, pitch and yaw are reversed on this QPD screen). Two of the diodes had significant improvements.  We then scanned with picomotor 1, which is closest to the array, and again decided to leave the beam centered on the QPD. I have not yet seen evidence of an improvement in jitter coupling from this centering. I suggest sticking with PD4 if we use only one.

Robert, Cheryl