The bias level (in ADU) is evaluated as the median value of all pixels in the master bias. As of 2015-04-22 the bias level is given after offset (overscan) subtraction (change after adopting new pipeline v.5). The trending is done for 2x2 binning only. The bottom pannels
show temperature in the focus of the instrument, read from the Chip1 and Chip2 data files. This is to trace any possible correlation of the bias level with temperature. Details can be found in the <a
href="http://www.eso.org/observing/dfo/quality/FORS2/qc/bias_qc1.html">plot tutorial</a>.

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<i>DB Name: fors2_bias <br>
TPL.ID: img_cal_bias <br>
Fits header keyword: QC.MBIAS.LEVEL <br>
QC1 DB parameter: median_master
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