Quality Control and
Data Processing

General information

PIPELINES AT ESO

Pipelines are used at ESO to process both calibration data and science data and to retrieve quality information. There is a dedicated pipeline for each VLT and VLTI instrument. Find general information about ESO reduction pipelines here.

FUNCTIONALITIES

The main functionalities of the pipelines are:

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

For selected instrument modes, we offer science-grade data products processed with the pipelines.

OPERATIONS

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 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.

XSHOOTER part

The XSHOOTER pipeline is publicly available here. Under this link you also find the pipeline Users Manual.

It has two modes of operation. In the physical model mode a configuration file with instrument model parameters is updated by analyzing the various calibrations. This mode is used for Quality Control as it provides more direct information on the instrument health. Therefore also the automatic processing of science data is done in this mode. The polynomial mode instead fits the calibration data with polynomials.

CALIBRATION and SCIENCE data

Find the description of XSHOOTER data processing and pipeline recipes for calibrations here and for science data here.

RAW DATA

XSHOOTER UVB-arm raw frames have a size of 2144 x 3000 pixel (unbinned) or 2072 x 1500 (1x2 binning) or 1072 x 1500 (2x2 binning).

XSHOOTER VIS-arm raw frames have a size of 2106 x 4000 pixel (unbinned) or 2106 x 2000 (1x2 binning) or 1052 x 2000 (2x2 binning).

XSHOOTER NIR-arm raw frames have a size of 2048 x 1100 pixel.

XSHOOTER AGC raw frames have a size of 562 x 528 pixel.

Find more details about the X-SHOOTER detectors here.

The UVB- and VIS-arm optical CCDs can be operated in low gain and high gain mode, which does not affect the number of frame pixel.

The NIR-arm detector is operated in non-destructive read out mode. NDIT exposures are averaged on the chip. For signals > 40000 ADU, the detector pixel switches from interpolation mode to extrapolation mode. Details are given in the XSHOOTER User manual.

RAW DATA EXTENSIONS

The raw frames don't contain any fits extensions.

PRODUCT FILES

Pipeline products have varying data formats. More details are described here.