After the vent, we noticed that the green cameras looking at the faces of the ITMs that we use for initial alignment references are quite off center. Also, Richard and crew have had prepared a new mounting system for those cameras, since any bumps to those cameras causes loss of initial alignment setpoints and lots of work for those trying to align the IFO. Since we are nicely aligned and able to lock, and need to recenter those cameras, Richard is taking the opportunity to also swap in the new camera mounts.
This morning, in prep, Sheila did an initial alignment of the green arms (using the camera setpoints) and offloaded the alignment. She then set the green arms to LOCKED_SLOW_WFS_ETM_TMS to keep the arms nicely aligned during the camera work, but in a way that does not actually use the camera setpoints.
Richard is now on the floor replacing the camera mounts, starting with ITMY's camera.
Before Richard began, but after the initial alignment + offload, I grabbed a screenshot of the cameras, just so we have an idea of what the change is. In the attached screenshot, the top row is live camera images showing where the green spots are. The bottom row is the saved version (using the 'take snapshot' button on the camera control screen), which includes the circular mask. This mask is applied before calculation of the centroid location (it's purpose is to help get rid of extraneous light that isn't the main beam), so this saved version on the bottom row is what the ALS ASC error points for the camera loops have been 'seeing'. The left column is the Yarm, and the right column is the Xarm.
Richard has finished work on the ITMY green camera. I have adjusted the camera mask settings to match the new image.
In the camera settings, "Circle Mask X" was changed from 250 to 335. "Circle Mask Y is unchanged and still 230. I also increased the "Circle Mask Radius" from 200 to 230, to account for the beam taking up more of the image.
In the attached screenshot of the green Y camera, the top is the live image (so, no mask) and the bottom is after having adjusted the mask, so the mask is on in the lower panel.
Richard and crew have finished the ITMX green camera, and I have adjusted that mask.
We set the green camera setpoints to the current position values, and are starting an initial alignment.
Attached is xarm, top=live, bottom=saved image with mask.
After an initial alignment, locking to 2W was nice and easy. After the IR 2W ASC converged, we reset all of the green initial alignment setpoints. The green QPD setpoints had quite minimal changes (as expected), and the only camera setpoint that needed a big change was ITMX's pitch setpoint.
Seems all good!
Work corresponds to progress on IIET Ticket 11931.