Aritomi and Yuhang

Today we realigned again the GR.

GR on the PR chamber target was fine. (See attached figure 1)

GR on the BS target was moved in the pitch direction. If I remember well, Eleonora intentionally removes the DC offset of PR local control. And after about two weeks, the pitch was misaligned. Maybe this means PR mirror has pitch drift without local control. (See attached figure 2)

Then we moved picomotor of PR to recover GR on the BS target.

We moved picomotor of BS to make beam go through the first iris. We also moved picomotor of BS again and made beam go through the second iris. After that, we found the transmission was not hitting the center of the camera. Since we think two irises along the filter cavity should be the best reference, we decided to move the camera to center beam on the camera. But we didn't move the fork of camera, so if this should not be done we can also recover easily. The situation before we moved camera was attached figure 3.