This plot displays a closeup view of the current last 10 days of extinction measurements 
with FORS2 standard star fields. It contains the pipeline results for the
extinction, with the instrumental zeropoint being fixed (read from a static table).

Check out the 
<a href=/qc/FORS2/reports/HEALTH/trend_report_EXTINCTION_BV_HC.html>extinction report</a> for 
the full record of existing data. The bottom panel displays the airmass of the contributing standard star fields, 
with the stability flag for the given night color-coded. Only data for chip 1 are displayed. This plot helps to monitor
the execution of the calibration plan for photometric nights. 
One can clearly see the inital low-high-airmass pair if acquired. We also
mark 'S'/'Sb' nights by a green bar, 'N' nights in red, and 'U' nights in
black.
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More information can be found on
the <a
href="http://www.eso.org/observing/dfo/quality/FORS2/qc/zeropoints/zeropoints.html">plot
tutorial page</a>.