I'm concerned that trying to solve for higher order optical aberrations coupled with motion of the HWS beam is causing problems in the parameterization of the HWS data. I ammended the HWS code to limit the parameterization of the wavefront gradient measurement to only pitch/yaw, spherical and cylindrical power. Additionally, I lowered the threshold on the intensity of acceptable spots to centroid on the HWS, increasing the number from 24 to 45. The noise in the measured spherical power was significantly reduced as a result (mostly from the simplification of the parameterization).

A plot of the measured spherical power noise floor referenced to the ETM is attached. The scale may be off in absolute magnitude by up to 20% due to the lack of a measurement of the magnification of the optical system as installed; the plot assumes the nominal 20x magnification.