Table of Contents
For HIFI, three Astronomical Observing Templates (AOTs) are available:
AOT I: Single Point, for observing science targets at one position on the sky;
AOT II: Mapping, for covering extended regions;
AOT III: Spectral Scanning, for surveying a single position on the sky over a continuous range of frequencies selected within the same LO band by the user.
Each AOT can be used in a variety of different modes of operation, providing the widest range of options for performing spectroscopic science observations in different astronomical that HIFI and the Observatory will allow, in terms of reference measurements and calibration. In other words, the three AOTs come with Observing Modes where the user may select from different calibration modes, choosing the mode best suited to the observing situation and science goals.
The Observing Modes are available to the user through the HSpot observation planning tool available in the Herschel Proposal Handling System.
The Observing Modes are described in the following sections, with typical usage examples and limitations, and steps for creating Astronomical Observing Requests (AORs) in HSpot, which represent real observations.
Regardless of mode, however, users of HIFI should be aware of the following general condition:
Only one LO band is planned to be operated at any one time, meaning that observations requiring frequencies in different LO bands will always require separate AORs. AORs making use of the same LO band can be scheduled together (e.g., via chaining), but the same scheduling restrictions that apply to different instruments will also apply to AORs requiring differing LO bands. For instance, it is currently not be possible to group or concatenate different instruments or, in HIFI's case, different LO bands together, under most circumstances.
Source integration times will be optimised according to the user's observing time goal or noise level goal. Providing user input is discussed in Chapter 6, where specific examples for setting up HIFI observations are given using the HSpot tool.