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Quality Control and
Data Processing

CAL | HC | refs | QC
Trending & QC1
   observing flat
QC links:
MATISSE: Flat field

The optical flatfield is measured through all optics of the MATISSE instrument. This calibration is necessary in order to compensate all space-variant gain table variations caused by the different optical paths (photometric and interferometric channels).
They are recorded each day when data on sky are taken.

hawaii observation flat field
hawaii observation flat field

OBS flat

An observation FLATFIELD and Bias maps are created for each scientific setup (geometry and exposure time).
The input data consist in one file containing 50 dark frames and one file containing 50 flatfield frames.
In addition, the static bad pixel map, the static nonlinearity map and the static flatfield map are needed.

  • The static bad pixel map (PRO.CATG = BADPIX) is needed to ignore the bad pixels during normalization of the optical flat. The static nonlinearity map is needed to separate the optical (large scale) variations from the fix pattern noise and the nonlinearity (small scale) variations.
  • The static flatfield map (PRO.CATG = FLATFIELD) is used to get the conversion factor for converting ADU into electrons and copy it into the optical flatfield.
  • The static non linearity map is needed to separate the optical (large scale) variations from teh fix pattern noise and the nonlinearity (small scale) variations.


    FITS key QC1 database: table, name definition class* HC_plot** more docu
    QC.DET..RON matisse_obsflat..ron_obsflat detector noise (electron) [docuSys coming]
    QC.DET..GAIN matisse_obsflat..gain_obsflat conversion factor (electron/DU) [docuSys coming]
    *Class: KPI - instrument performance; HC - instrument health; CAL - calibration quality; ENG - engineering parameter
    **There might be more than one.


    There is no trending of the values of the QC parameters. The GAIN and RON are copied from the input static calibrations

    Scoring&thresholds OBS flat

    There is no scoring of the HC plots for observation flat field.


    Algorithm OBS flat

    The recipe used is called mat_est_flat
    The pixel statictics are calculated for the DARK and FLAT images.
    The instrument flat field is estimated

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