This is the trending plot for the ISAAC twilight flat QC parameters of the SW-arm

These plots describe:
The master flat has been divided by a reference master flat to get rid of the high structural noise (fixed pattern noise). On this differential frame, a histogram is generated and is fit by a Gaussian to retrieve a robust pixel statistics and the width is retrieved. This width is a robust estimate of variationsin the structural noise. Renewal of the reference flats are indicated.

QC parameters have not been calculated by the pipeline but by post-pipeline QC scripts, hence there are no values from Paranal to be included.

Fig.1. upper left quadrant of the detector.
Fig.2. upper right quadrant of the detector.
Fig.3. lower left quadrant of the detector.
Fig.4. lower right quadrant of the detector.

The color coding is : green for H, blue for J and Js, red for K.

This QC1 parameter is sensitive to changes in the structural noise, which can be due to changes in the fringe pattern, instrumental internal reflections and the structural noise of the detector itself.

Find more information about ISAAC QC parameters derived from twilight flats here.