4.7 Duration

The completed AOT is displayed in Fig. 4.14.

**Figure 4.14:** The completed IRAC AOT for Abell 2218.
$\begin{figure}\centering \epsfig{figure=figs4f/deep_imaging_irac_aot_completed.ps, width=5.0in} \end{figure}$

Hitting ``OK'' on the AOT entry dialog window returns us to the main Spot window, as shown in Figure 4.15.

**Figure 4.15:** The Spot menu after the IRAC AOT parameters have been entered.
$\begin{figure}\centering \epsfig{figure=figs4f/deep_imaging_irac_aot_entered.ps, width=5.5in} \end{figure}$

Hint: in this example, we gave the AOR the title ``IRAC mapping - a2218.'' Note that all alpha-numeric characters are not permitted in the AOR name. Periods and colons are not allowed. Also, make sure to give each AOR a unique, short and yet insightful name. The AOT entry dialog will assign a label by default, but we highly recommend changing this to more reflect the nuances of your observations.

A feature to notice: under duration, there is no estimate of time required to execute this AOR. Easy enough to fix: under the ``Tools'' pulldown menu of the main Spot window, select ``Recompute All Estimates.'' You will be greeted with a pop-up menu asking you to select what you want to recompute. Select ``Current AOR.'' Spot will then churn away in the background, and return you to the main spot window, with the ``Duration'' field now filled (11124.8 seconds, for this example). Also the Total Duration report on the bottom right of the Spot window will be filled. In this example, we use 3.1 hrs, which is less than the maximum of eight hours per AOR allowed for IRAC observations. A screen capture of the Spot menu with the duration estimates included is shown in Fig. 4.16.

**Figure 4.16:** The Spot menu after the Abell 2218 IRAC AOT parameters have been entered, and the AOR duration computed.
$\begin{figure}\centering \epsfig{figure=figs4f/deep_imaging_irac_a2218_duration.ps, width=5.5in} \end{figure}$

Hint: an alternative way of obtaining the AOR duration is to click on the ``Calc. Obs. Time'' button from within the main AOT entry window (see Fig. 4.14). The duration estimate returned will now include a breakdown of slew time required, settle time, total AOR duration, and the integration depth in seconds, per pixel, for each of the passbands. See Figure 4.17 for a screen capture.

Gillian Wilson 2006-11-09