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VISIR pipeline:
general information

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Trending & QC1
general info
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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.


The VISIR data reduction pipeline is available from the ESO pipeline pages.


The VISIR pipeline supports most offered modes, except for Echelle spectroscopy.


The file format after the upgrade, i.e. for P95 (April 2015) and later, has fits files where all data is stored in extensions. The primary header unit is empty:

  imaging spectroscopy
format (X,Y),
1x1 binning
1024 x 1024 px
1024 x 1024 px
half-cycle frames
2 per chopping cycle
integration frame yes (1 per file, i.e. nodding position) yes (1 per file, i.e. nodding position)

Pre-upgrade raw files were fits without extensions, detector size was 256 x 256 px.



Packages with the data of the Service Mode runs executed prior to October 2011 (Period 87) were sent on DVDs. Otherwise, the packages are available to PIs via the User Portal. They contain

  • all raw science data,
  • reduced science data,
  • associated calibration products,
  • associated raw calibration data,
  • listings and logs,
  • QC reports and OB reports.

  Data packages

[ QC Home page ]