Quality Control and
Data Processing

HC PLOTS
Flat flux stdev, filter Y
Flat flux stdev, filter J
Flat flux stdev, filter H
Flat flux stdev, filter Ks
QC1 database (advanced users): browse | plot

The Twilight Flats trending is based on the measurement of QC1 parameters from the twilight flat field calibration data. Following the calibration plan, the twilight flat fields are taken during evening (usually) and morning (rarely) twilight with clear skies. This is done whenever they are needed to calibrate SCIENCE data. HAWK-I instrument does not have an internal lamp. In the infrared, twilight flats are taken by sampling a large flux range by integrating on the twilight sky as the Sun sets or rises. Twilight flats are therefore one of the most time critical calibrations because of the narrow time window during which they can be acquired.

QC1_parameters

FITS key	QC1 database: table, name	definition	class*	HC_plot**	more docu
QC.FLAT.MEDSTDEV	hawki_twflat..qc_flat_medstdev	Standard deviation of median values	CAL		[docuSys coming]
*Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter **There might be more than one.

Trending

The standard deviation of the pixel values in a stack of the input frames is monitored for each detector in Broad Band filters J, H, Ks and Y.

Scoring&thresholds TWILIGHT flat flux range

The standard devition, as a rough measure of the flux range, is scored loosely, with dynamic thresholds following the median average of the current period.

History

No major historical issues

Algorithm TWILIGHT flat flux range

The pipeline estimates standard deviation of the pixel values in each individual stack of the input frames.