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AOS Engineering Analysis

AOS and Hexapod regression

In this regression, two exposures were taken with the AOS on to set the alignment and focus. This defined the hexapod "zero" position for the following test during which the hexapod trim x values were moved over a range of 2000 greater than and less than the value found during the AOS calibration. The y value remained at it's calibrated value. The step size was 500 microns. Then, the trim y values were moved over a range of 2000 greater than and less than the value found at AOS calibration. The x value remained at it's calibrated value.
We did not allow the AOS to reset the alignment between the x and y tests nor was the telescope moved back to the starting position after the x test - this might have been a mistake.

Image quality analysis

Data taken for the trim x values

The first two points are the calibration exposures. The line is the range of trim_dx's used.

This plot shows a clear curve with a minumum centered at the AOS calibrated location (trim_dx = -214.33).

The above plots show a clear curve, with a minimum wider than the previous graph but which does contain the AOS calibrated location (-214.33).

Overall, the trim_dx plots show the AOS working the way we would expect.

Data taken for the trim y values

The first two points are the calibration exposures. The horizontal line is the x exposures being taken, for which the
y trim values were kept at the calibration values. The first diagonal was a range of exposures for which the x value was
set incorrectly. The second diagonal, highlighted in blue, is the set that was used in this analysis. The x value of trim
was held at the calibration value for these. The position from the AOS is trim_dy = -78.36.

The above plots for trim y do not show as clear a curve as the trim x did. The calibrated value they should center around is -78.36.
Perhaps this was due to the telescope tracking and hence changing position over the duration of the test. As mentioned before the alignment was not reset (with the AOS) between the x and the y test.

Look Up Table

The look up table values varied minimally during these tests, especially in comparision to the tweak values, as can be seen below.