The HIFI (Heterodyne Instrument for the Far Infrared) observer's manual is intended to assist in using the HIFI instrument on board ESA's Herschel Space Observatory. Documents on the detailed documents on design and operations are available from the Herschel Science Centre (HSC) and the HIFI Instrument Control Centre at SRON, Groningen, The Netherlands (HIFI ICC -- who are responsible for the safety and calibration of HIFI during operations).

Help and information on HIFI can be obtained by contacting the Herschel Science Centre at the following web address:

http://herschel.esac.esa.int

Follow the link on the page to the "Helpdesk" for problem enquiries.

This document contains overview information on instrument concept and design, its scientific performance and calibration. It also contains all user-relevant information on observing modes and Astronomical Observing Templates (AOTs) Examples of AOTs for HIFI are presented with their usage.

HIFI data from the Herschel Space Observatory are automatically processed at the HSC after the data is received from the spacecraft. The standard processing - pipeline - is described here together with a description of the data products. Both the raw and pipeline processed data are made available to the user.

Finally, a brief mention is made of software tools that have been more specifically provided for the kinds of sophisticated analysis that is likely to be needed for HIFI data reduction. These will available to the user through the Herschel Common Science System, which will be made available by the Herschel Science Centre. It should be noted that all pipeline software modules are available to users via installation of the Herschel Common Science System. Reprocessing of data can therefore be performed with pipeline, or adapted pipeline, scripts by users on their own workstations.