2.4.4 Obtain Resource Estimates

As noted in §2.4, the fundamental unit of Spitzer observing is the Astronomical Observation Request (AOR). An AOR can not be subdivided, will not be interrupted for other activities (such as downlinks), and will be handled as a unit by Spitzer. Because an AOR will be executed as a unit, and the need for the Observatory to perform certain activities (such as calibrations, detector anneals, downlinks), there is a maximum duration for an AOR: eight hours for IRAC and IRS AORs, ; still three hours for MIPS AORs . AORs that would require longer time-blocks to execute must be divided into separate requests (i.e., shorter duration AORs).

At any time within Spot, you can check how long an AOR (or series of AORs) will take to execute. From the main Spot window (see Fig. 2.1), look in the ``Tools'' pulldown menu and select ``Recompute All Estimates.'' You will be greeted with a pop-up menu asking you to select what you want to recompute. Most often, you will select ``Current AOR,'' ``Selected AORs'' or ``All AORs.'' Spot will then churn away in the background, and return you to the main Spot window, with the ``Duration'' field filled in the lower right-hand corner of the Spot window, and duration estimates listed for each AOR.

To obtain more detailed information about how the total duration is shared among actual integration on-sky, telescope slew time, settle time, and so on, use the ``Calc. Obs. Time'' button within each AOT entry dialog. See §5.5 for a detailed example within a MIPS Photometry/Super Resolution observation.