Quality Control and
Data Processing

To compensate for possible flexure of XSHOOTER a pinhole arc frame is taken before every science frame, from which the line shift relative to reference positions is determined (and then compensated by the piezo-controlled mirrors). This shift in X and Y is stored together with other parameters for later analysis. These QC parameters are specific to the acquisition of the individual science OB (pointing) and less related to the instrument health.

The values are not monitored. They are available as shift_x and shift_y in the flexure QC1 DB.