Following on from alog 90738, we last had the corner alignment with the BBSS at PIT +115 and YAW -1557. We decided to offload this YAW to the HEPI so the team embarked on that yesterday, likely another alog from IAS/SEI on that move later. Today we went and looked at the corner beam pointing with Keita refining the BBSS alignment to PIT +107, YAW +441 (see his alog coming).
So now, Jim and Mitchell are embarking on Actuator attachment at the piers. We will relook at the BBSS cage position with the FARO shortly after they are complete, and then re-peek at the corner alignment likely early next week.
Meanwhile, the BBSS PIT to YAW cross coupling investigaton continues...
We took a FARO shot before the HEPI rotation, shown in the 1st attachment, and one after, shown in the 2nd attachment. The FARO measures the yaw rotation at 0.0773°, or 1.35 mrad, in the clockwise direction (44.9990 - 44.9217 = 0.0773; direction is CW since we rotated closer to the +X axis). At this point we had some interference between one of the spring caps for the -X/+Y HEPI pier and the -X blue HEPI crossbar, so we could not rotate any more (Jim cleared the interference this morning by removing the spring cap and grinding some material away). Regardless, this was enough to get us to an acceptable place. In addition to the rotation, we did see some -X position shift in the BBSS cage, as can be seen in the attachments. Averaging out the the rotation gives a shift of 1.4 mm in the -X direction. From the test stand alignment the BBS optic itself was +0.3 mm in the X direction w.r.t. the ISI, so the BBS is now roughly -1.1 mm from its ideal X axis position. Using the same position tolerance from the test stand of +/-1.4 mm, this means we're pretty close to the edge for X axis position but still within, so onward we go.
We'll measure the position again once all the HEPI actuators have been attached to ensure position is still good, as there is potential for things to move during actuator attachment.