HAWKI: Twilight flat
| Flat flux stdev, filter Y
| Flat flux stdev, filter J
| Flat flux stdev, filter H
| Flat flux stdev, filter Ks
QC1 database (advanced users):
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.
TWILIGHT flat flux range
||QC1 database: table, name
| 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.
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.
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.