Astronomical observations with ISO were carried out via pre-planned observing modes. These are modes in which the basic operating parameters for the instrument are predefined (e.g. which sub-instrument to use at what wavelength resolution), leaving the user to select wavelengths to scan between, enter flux levels etc. Almost all observations entered by observers used one of four Astronomical Observation Templates, AOTs, while calibration observations used a variety of AOTs and Calibration Uplink System, (CUS) observations. The AOTs are fully described in Beintema & Kunze 1999, [1], to which users are pointed if this section does not provide them with sufficient information. CUS was a very flexible system to define observations for calibration purposes which very well could contain valuable astronomical information. It was also used to define a specialized AOT for the Post-Helium Phase.
The EOHAAOTN keyword, present in the product files (see Appendix A), indicates what type of observation was performed. For normal AOTs it will take the value S01, S02, S06 or S07. For CUS or post-helium observations it will take the value S99, while S90 - S98 were reserved for engineering operations such as activation and de-activation. During the mission changes were made to the AOTs as experience with the instrument increased. A list of these changes is given in Appendix C.
In this book the AOTs will be indicated by their official designation: SWS01, SWS02, ... SWS99 to distinguish them from AOTs with possibly similar names in use by the other instruments.