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AMBER Quality Control:
Analysis of the fringe files

CAL | HC | refs | QC
Trending & QC1
QC links:
QC1 database (advanced users): browse | plot
   Click on CURRENT to see the current trending (Health Check).
   Click on HISTORY to see the historical evolution of the trending.

AMBER observations are done with different resolutions and in different spectral bands.

  • Low Resolution with 3 bands JHK
  • Medium resolution with only the K band offered for SM observations (MR-H offered for P84)
  • High Resolution in the K band
  • One observation consists in a set of raw files with a DPR TYPE=OBJECT, one SKY and one DARK file. A valid P2VM is available to process each observation (calibrator or science). The BPM and FFM used to reduce the data (fits files) are available here There are also calibrator observations done during the night with the same instrument settings.

    For SM observations, there are some rules to be followed:

  • the P2VM should not be older than 4 hours
  • the calibrator observation associated to the science should be taken within one hour
  • Each OBJECT file is processed by the pipeline recipe SciCal which generates products (1 product per spectral band). Some plots are also produced for QC processing (data quality checks for example). An example of a K band low resolution plot is shown here.

    Each product contains several extensions as shown bellow. The extension AMBER_VIS2 is shown in the middle, AMBER_DATA on the right.

    The product files generated by the SciCal recipes are not filtered, the recipe amber_selector can be run to further select the frames following different criteria.

    QC1 parameters

  • QC.BAND : spectral band of the product (for Low Resolution JHK, there are 3 products per raw fits file with QC.BAND=J, H, K
  • QC.STA1/2/3: telescope station 1, 2 and 3. These stations are coded and the corresponding station can be found in the extension OI_ARRAY. For example UT1 is station 31, UT2 is 32, UT3 33, UT4 34.
  • QC.FRAMES.SELECTED.SNRGT2, number of frames found with a SNR >=2
  • QC.FRAMES.SELECTED.PERCENT, percentage of frames found with a SNR >=2
  • QC.CEN.xxxxxx, QC parameters calculated over the central 80% of the spectrum
  • The products are analysed for different issues:

  • SNR
  • percent of fringes left after filtering
  • SNR on the fringes for the different baselines
  • Vis on the fringes for the different baselines
  • std of the Vis on the fringes for the different baselines
  • the cutoff wavelength in case of a K observation.
  • top Visibility

    The Vis2 is calculated by the pipeline and found in the extension OI_VIS2. The HC plots show the VIS2 obtained during the night.

    Trending and history

    top wavelength cutoff

    In low resolution, we encountered in the past (first discovered in September 2007 to January 2008, then mid-2008) some problems with the grating which caused a cutoff in the spectruum to a value lower than the expected one (up to 2.54 micron). Since mid-2008, we are monitoring these values. The current HC plot is shown here .

    The cutoff at a value lower than 2.35 are marked as outliers

    The value are calculated by a QC procedure and ingested in the QC1database. The HC plots show the SNR obtained for the different resolutions. Only the results for the K band are shown. The top plots compile all the data, when the bottom plots show only the SM data.

    QC1 parameters

    Several parameters are logged in the QC1 database

  • lambda.max
  • lambda.min
  • chan.max
  • chan.min
  • Trending and history

    The lambda.max values are trended for SM and all data. The values are shown for both science files and astronomical calibrators.