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.

Find the description of CRIRES data processing and pipeline recipes here:

CRIRES pipeline
calibration
science reduction

All settings offered for Service Mode are pipeline supported.

Since October 2011, QC Garching processes only calibration data from CRIRES. Before that date, all calibration and science were processed.

Raw data. The CRIRES detector is a 4x1 mosaic of 4 Aladdin III arrays, each with 1024x1024 pixels. Only the lower 512 pixels of each array are read out so that the total mosaic consists of 4x1024x512 pixels. The pixel size is 27 microns. A fifth Aladdin III detector is used in the slit viewer. The arrays are read out using standard ESO IRACE controllers with 64 channels (4x16) for the science arrays and 32 channels for the slit viewer, respectively.

Extensions. Raw calibration and science data come as FITS files with one primary header unit (HDU) and four extensions. The primary HDU has all keywords necessary to identify the observation and the state of the telescope and the instrument; the data part is empty. Pixel data are stored in the extensions, one extension for each array.

Acquisition frames have only a primary HDU containing keywords and the slit viewer image.

Products. Pipeline products have varying formats. Wherever appropriate, also product files have four extensions with the relevant product data for each array (either pixel data or fits tables).

Windowed read-out. Beginnig with Period 84 (October 2009), a windowed read-out of detectors 2 and 3 is offered. Two stripes on each detector can be defined, each with 32, 64, or 128 pixels size in Y direction. In dispersion direction (i.e. in X), the full detector is read. The stripes are available in extensions 2 (stripes for detector 2) and 3 of the raw frame. Detectors 1 and 4 are not read; the corresponding fits file extensions have empty images.

All packages are available to PIs via the User Portal. Until Period 87 (April to September 2011), runs performed in Service Mode received also a set of DVDs containing

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

  Data packages