Tuesday the ISI table level was checked and found to be within 0.2mm, and on Wednesday we performed initial yaw measurements (yaw measured at 2.61 mrad).
Yesterday we measured the ITM yaw and horizontal position. The yaw was confirmed to be 2.6 mrad out of alignment (initial measurement done Wednesday) but the horizontal position was found to be 0.46mm from center, which is well within the ±1mm spec.
As Betsy stated in her alog we were able to correct the ITM yaw to ~400 µrad (the spec for rough yaw alignment is ±1mrad). After this we used the Microscribe to measure the gap between the corner cube retroreflector (used for y-axis distance measurement) and the ITM so we could get an accurate meaurement of the y-axis (longitudinal) position of the ITM. This gap was measured at 52.6mm and the total station measured 6982mm to the corner cube, resulting in a total distance from the total station to the ITM of 7034.6mm; the desired distance in 7041.3mm, so this shows the ITM structure to be to far forward on the ISI by 6.7mm. We are currently looking for the source of this error. Since the structure was moved in yaw, we also need to recheck the horizontal position of the ITM to ensure it is still within spec; these 3 degrees of freedom (yaw, horizontal position, and longitudinal position) need to be checked every time the structure is moved.
We are currently looking for the source of the FM longitudinal error as well.