[Thomas, Elli, Aidan]

We re-aligned the pick-off from the ETM HR surface onto the Hartmann Wavefront Sensor (HWS). Several wedged uncoated optics were used to attenuate the beam before the sensor. We adjusted the combination of these until the beam was not quite saturating the CCD on the sensor.

We removed the Hartmann plate from the CCD and recorded the beam profile. There were diffraction rings on the edges of the intensity distribution which we assumed was caused by clipping on a couple of optics. Tweaking the alignment removed some of these effects but there is still significant clipping on the right hand side of the image that we've yet to identify the cause for [see attached PDF].

The Gaussian beam radius in the vertical direction on the HWS is roughly 1.95mm. We expect a beam size of 1.57mm. We need to adjust the magnification in the HWS telescope and confirm that we're imaging the ETM HR surface.

We replaced the Hartmann plate and ran the sensor overnight.