Quality checks for VISIR data are applied in the same way as for data from other VLT instruments.

The QC checks consist of

• Quality Control Level 0 (QC0, ambient observation constraints)
• Quality Control Level 1 (QC1, per pipeline product)
• trending (parameters as a function of time)

The following type of QC products are provided

• QC1 parameters of pipeline processed calibration product (master calibration). These single numerical values should be eventualy accessible from a local database in plain ascii format.
• QC1 plots showing the most important properties as a function of time.
• Trending plots of several QC1 parameters, showing the long term behaviour of individual instrument properties. These plots will be available in gif and ps format.

QC0 involves checks whether the user-defined observational constraints have been respected during the observation. QC0 checks are executed on raw data.

The Service Mode observer receives a QC0 report which lists all programme-specific science files, their user-defined constraints (as read from the OB Repository which was filled from P2PP), and the actual QC0 parameters during observation (as read from the Ambient Database which is fed from the Ambient Site Monitor).

Furthermore, the user also receives extracted night logs including an OB report which contains, per OB, the assessment by the on-site staff of the quality of the raw data.

The data are checked for the following constraints:

• airmass,
• moon distance,
• fractional lunar illumination (FLI),
• seeing.

Find more information about QC0 reports here.

Please note that the packages including the above reports have been discontinued since October 2011.

Quality Control Level 1 consists of quality checks on pipeline-processed data.

Information on VISIR QC1 and trending can be found here.

Trending is monitoring QC1 parameters over time (e.g. effective resolution as function of time). Investigating mutual relations of QC1 parameters is also part of trending. Information on VISIR QC1 and trending can be found here.