4.2 Quality Check of the Data

The LWS data products for AOTs L01, L02 and L04 have been Quality Checked. This was to ensure that no corrupted data is distributed. The quality check was performed at three levels.

Level 1

Here the OLP operators checked the products of the processing for obvious errors like:

• Instrument failures or telemetry drops during the observation
• Absence of a spectrum
• A non-physical (i.e. negative) spectrum
• A flat spectrum (i.e. all values equal)

If an anomaly was detected at this level, it was passed to Level 2

Level 2

Here the instrument team investigated whether the failure was due to an instrument failure, or a peculiar behaviour of the instrument and decided if the observation was still scientifically valid. If this was not the case the observation was passed to Level 3.

Level 3

Here the astronomers in the ISO team investigate whether the observation needed to be rescheduled (when ISO was still in operation !), or whether the observation would most likely fail again (for instance due to very high backgrounds, or proximity to a very bright source).

The data observers got for the AOTs L01, L02 and L04 should therefore not contain any obvious errors (as listed above). For LWS the products of AOT L03 (FP wavelength range) have not been scientifically validated and have therefore not been Quality Checked.