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Quality Control and
Data Processing

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MOS: calib data
Solar&sky spectra
QC links:
UVES: MOS Calibration data
| Raw files | Calibration products | Calibration Cascade


Calibration data are taken for two purposes:

  • to calibrate SCIENCE data
  • to measure and control the instrumental status

    Generally UVES-MOS calibration data are taken as day-time calibrations. On request by the user, also night-time calibrations (flat fields) can be obtained as part of the Observing Block which generates the SCIENCE data.For high-precision radial velocity studies, it is also possible to record an arc lamp spectrum simultaneously with the SCIENCE data.
    All day-time calibration data are processed by QC Garching to obtain calibration solutions. These solutions come as

  • master calibration files (master BIAS, master FLAT),
  • calibration products like dispersion tables.
    Raw files
    | Raw files | Calibration products | Calibration Cascade

    Calibration Raw Data

    The following table contains an overview of the raw calibration files for the UVES echelle mode. The data types are identified with the DPR TYPE keyword of the fits headers.
    frame DPR TYPE Purpose typical number taken at night
    BIAS BIAS detector status, bias level 5
    DARK DARK dark current 3 per month for monitoring
    FORMAT CHECK LAMP,FMTCHK,SimCal align spectral format to physical model 1
    ORDER DEFINITION FLAT LAMP,ORDERDEF,SimCal define position of orders and interorder background 1
    SLIT FLAT LAMP,SFLAT fix-pattern noise, fringing, slit function, blaze function 3 frames in 3 slit positions
    FIBRE FLAT LAMP,FLAT,ODD LAMP,FLAT,EVEN LAMP,FLAT,ALL define fibre positions, correct for fibre cross talk 1 ODD-EVEN-ALL set

    SLIT FLATs are similar to UVES Echelle flats but are taken in three different slit positions so that the whole space between two orders on the chip is covered. FIBRE FLATs come in three different varieties: with only ODD numbered fibres illuminated, with only EVEN numbered fibres illuminated, and with ALL fibres illuminated. All three varieties are measured in a sequence.
    Examples of raw UVES-MOS frames and FITS headers are available from the FLAMES-UVES reference frames page.
    For a complete overview of the data types and their dependencies, check the calibration cascade.

    Calibration products
    | Raw files | Calibration products | Calibration Cascade

    Calibration products

    The following table contains an overview of the products calibration files for the UVES echelle mode.
    raw frame(s) recipe description product(s)
    BIAS [bias_th.gif 3K] uves_cal_mkmaster create a master bias from set of input raw frames MASTER_BIAS
    DARK uves_cal_mkmaster create a master dark from set of input raw frames MASTER_DARK (only occasionally produced)
    FORMAT CHECK [fmt_th1.gif, 2K] flames_cal_predict obtain first guess wavelength calibration solution FIB_LIN_GUE, FIB_DRS TABLE
    ORDER DEFINITION FLAT [order_th.gif, 2K] flames_cal_orderpos define order table and background table FIB_ORDEF FIB_ORD_GUE table FIB_DRS table
    SLIT FLAT [sflat_th.gif 2K] flames_cal_mkmaster create a master flat from set of input flats MASTER_SFLAT
    FIBRE FLAT [fflat_th.gif 2K] flames_cal_sff_ofpos create a master flat from set of input flats FIB_ORDERDEF_TABLE FIB_FF_* SLIT_FF_*
    WAVELENGTH CALIBRATION [wave_th.gif 3K] flames_cal_wavecal obtain wavelength calibration solution FIB_LINE_TABLE, FIB_DRS_SETUP_TABLE

    If there are several sets of daytime calibration data, only one is processed. If there are one or several sets of night-time calibration data, they are all processed.

    Naming scheme

    After production and certification, the calibration products are renamed after a scheme which includes type, creation data and relevant FLAMES/UVES setting parameters.
    The naming scheme can be found here

    Calibration Cascade
    | Raw files | Calibration products | Calibration Cascade

    Calib cascade

    The processing of FLAMES/UVES calibration frames requires a cascading scheme where the mutual dependencies of products and raw frames have to be respected. Some products (master bias, first guess line table) can be produced from raw files only, but most products require the prior generation of other calibration products. The proper sequence of all these production steps is called the calibration cascade (see here ).
    Within that cascade, all products are checked with respect to their quality and their relationship in time. This means e.g. that a master flat is not only generated using an arbitrary quality-checked order table, but that specific table is chosen which at the moment of processing is closest in time.
    All products created by QC Garching respect the calibration cascade.

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