The recipe midi_profile is applied to chopped PHOTOMETRY frames.  For
each window on the detector (Data1, Data2 for HIGH_SENS) and Data1 to
Data4 for SCI_PHOT, a profile is identified and a mask is created. The
recipe also calculates the y position of the mask in 5 different bins
<br>

These results are used to monitor the vertical position of the
spectrum (using the bin 3: HIERARCH ESO QC Y1 CENT BINNED3).  A
problem has been detected with the PRISM (the y position is moving 1
pixel per year).<br>