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general info
Data Management
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This page provides information about pipeline processing and data types.

Raw data are selected, associated and inserted into a reduction mechanism which produces calibration products, science products and quality control information. This mechanism is the data processing pipeline. There is one such pipeline for each VLT and VLTI instrument.

Find general information about ESO reduction pipelines here.


The main functionalities of the pipelines are:

  • create master calibration data,
  • reduce science frames,
  • extract QC information from the data.

QC Garching creates master calibration data from all raw calibration data. The raw data are stored in the ESO Archive and are public. They are quality-checked and used for data reduction and for trending.

Before October 2011 QC Garching processed science data, using the best available, quality-checked master calibration data. As of October 2011 this service is not offered anymore.


There are two instances of the data reduction pipelines:

  • at the instrument workstation on Paranal, running in automatic mode,
  • at HQ Garching, run by the Quality Control Group in the optimized mode.

The automatic mode is used for quick look purposes and for on-site quality control. It processes all raw data sequentially, as they arrive from the instrument. If calibration products ("master calibrations") are required for processing science data, these are taken from a database with standard, pre-manufactured calibration products. The automatic mode is not tuned to obtain the best possible results.

The optimized mode is the mode, which uses all data of a night, including the daytime calibrations. The calibration data are sorted and grouped according to their dependencies. Master calibration data are created. Their quality is checked.

AMBER pipeline

Pipeline products from AMBER are stored as FITS binary table files using generalized Optical/IR interferometry conventions. Find informations about this format here. More details can also be found in this document.

The Pipeline is available from here.

Until October 2011 all science data were processed by QC Garching. This has been stopped now, and only calibration data are pipeline-processed by QC Garching.

All the raw data taken on an astronomical calibrator are processed by the pipeline. In some cases, the automatic pipeline can not reduced the raw files, in this case no pipeline products is produced.


A set of raw data should includes:

  • internal calibration files, optionnal spectral calibration files (used to calculate the P2VM),
  • acquisition frames and injection adjustment frames,
  • fringe-search files,
  • observations.

The following table shows some of the main keywords for the different raw files

type of observation template DPR CATG DPR TYPE DPR TECH comment
technical detector calibration Bad Pixel Map CALIB BADPIX    
technical detector calibration Flat Field Map CALIB FLATFIELD    
technical calibration Beam Position CALIB STD IMAGE position of the Beam for all the settings
instrumental calibration (spectral calibration) Pixel to Visibility Map CALIB WAVE,2TEL or WAVE,3TEL INTERFEROMETRY  
instrumental calibration (P2VM) Pixel to Visibility Map CALIB 2P2V or 3P2V INTERFEROMETRY  
Calibration of the background emission (associated to fringe observation) Observation CALIB or SCIENCE DARK INTERFEROMETRY  
Calibration of the background emission (associated to fringe observation) Observation CALIB or SCIENCE SKY INTERFEROMETRY  
scientific observation Observation CALIB or SCIENCE OBJECT INTERFEROMETRY  



f the file is set with the DPR CATG keyword in the primary header of the fringe-track FITS file.

Two different types of files carry a DPR CATG=CALIB :

  • Technical and detector calibrations
  • all the files associated to an astronomical calibrator.

All the files with a DPR CATG=CALIB are not proprietary and will be available from the science archive .


The science data (DPR CATG=SCIENCE) are not processed by QC but the raw files are available from the archive . The master products to be associated with the science files can be obtained using the calselector option.



The raw data taken with the VLTI are processed twice :

  • at the VLTI complex on Paranal, using a fully automatic mode, and allowing the astronomer to have a quick look at the data and for on-site quality control,
  • at the headquaters in Garching. This processing is done on the astronomical calibrators on full nights and the calibrations are certified. The quality of the results on the P2VM and on the astronomical calibrators is assessed.

    Each product is named following some rules (product_codes.html for the calibration files.

The pipeline delivers visibilities for each baseline and each spectral bands for the astronomical calibrators. If the object is in the calibrator catalog, a Transfer Function is also calculated. These products are used to assess the quality of the calibrator observation and to certify if they could be used to be further associated to the science data.



The pipeline supported modes for P80 are the data taken with the standard observation template : Obs_Std. The following table shows the type of files and the pipeline recipes used to reduce them. More details on the pipeline recipes can be found here. More on the file associations can be found here.


observing template type of object type of file DPR TYPE pipeline recipe pipeline product comment
AMBER_bpos instrumental calibration raw


amber_bpos AM_MPOS_name.fits (see here ) Position of the beams
AMBER_p2vm instrumental calibration raw


2P2V or 3P2V

amber_p2vm AM_MPVM_name.fits (see here ) P2VM, with spectral calibration (if WAVE files)

astronomical calibrator

science object





amber_SciCal AM_MFR_cname.fits (for calib) or AM_SFR_sname.fits (for science) (see here ) dispersed visibilities


The delivered products are in format of ASCII files in the logs directory of the Data Package (association files, pipeline and association logs), and FITS files.



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