The HIFI Observers' Manual (HTML and PDF versions can be found at http://herschel.esac.esa.int/Docs/HIFI/html/hifi_om.html and http://herschel.esac.esa.int/Docs/HIFI/pdf/hifi_om.pdf respectively) provides basic information on the instrument, how the instrument works and its use. Several examples for setting up science observations with HIFI are also provided.

HIFI has three basic AOT forms for pointed, mapping and spectral scan observations. Several reference schemes are available for each type including dual beam switch (DBS) and frequency switch -- amongst others. The following sections describe the AOTs and the modes available within each AOT.