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:
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:
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 ISAAC data processing pipeline is operational since April 1999 (ESO observing period 63).
The ISAAC pipeline is publicly available (check out here). Under this link you also find the pipeline Users Manual.
Find the description of ISAAC data processing and pipeline recipes here:
Both in Service Mode and Visitor Mode, ISAAC observations are supported in the following instrument modes:
The following instrument modes are not supported by the pipeline:
QC Garching currently processes the following ISAAC data:
We maintain a log file showing the link between the pipeline versions and the date from which on it was used for.
Raw data. The short-wavelength arm of ISAAC is equipped with a Hawaii array with 1024 x 1024 pixel. The long-wavelength arm has an Aladdin array of 1024 x 1024 pixel.
The Hawaii array is operated either in double correlated or in nondestructive read mode. The file format is a single FITS frame with a single header unit. The Aladdin array is operated in uncorrelated read mode at high bias or in double correlated read mode. The latter one operates in high bias or low bias read mode. The file format of the LW-arm Aladdin array depends on the instrument mode. Table 10 of the ISAAC User Manual shows the links between detector operations mode and instrument mode.
The ISAAC Users Manual has also a detailed description of the ISAAC raw data structure.
Products. Pipeline products have varying formats.
Since April 1999 (ESO observing period 64) , observing runs performed in Service Mode receive a data package containing