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BCAM Alt-Az Scans

Here are BCAM measurements for the Alt-Az LUT scans taken in November, January, and March. This first plot shows the raw BCAM measurements, without any means subtracted out.

Clearly, the BCAMs are measuring large changes in the absolute alignment of the mechanical collimation. To more easily compare relative changes, we can subtract out the means of from each of the plots.

Here we see that the relative differences are smaller than measured by the donuts, though this does not explain the large changes in the absolute alignment. Our solid model of the BCAM mounts predicts the maximum contribution to the BCAM measurement from flexure will be < 100um. This suggests that these large changes measured by the BCAMs are due to actual changes in the mechanical alignment.