2.2.1 Are the targets available for observations with Spitzer?

Assuming you have targets selected for observations with Spitzer, you will need to be armed with a bit of information before launching into designing the observations themselves: first, can Spitzer view your targets?

The short answer is that all locations in the sky will be observable by Spitzer for at least $\sim 80 \; {\rm days}$ per year, even if Bright Object Avoidance is needed near the ecliptic. However, if there are any timing constraints on your program in addition to the visibility windows allowed by this general Sun-pointing constraint (for example, you require a certain position angle for the observations), you will need to make sure that they are consistent with the windows of visibility allowed by the Sun-pointing angles. For example, if your observations are highly sensitive to slit orientation, there might be only a few days in the year when the geometry of the spacecraft will give the desired slit orientation. Or, no days at all (in which case, the observer has to reconsider which slit orientations are required)!

To determine the target's visibility from Spitzer, one can employ the ``Visibility/Orientation'' button within the ``Target window'' of the Spot software.

Since the Spitzer Space Telescope has the capability of observing the entire sky at least once per year, your targets will be, at some time, available for observations. Another issue, however, is duplicate observations. In order to ensure the most efficient use of Spitzer, proposed observations that duplicate those already executed, or approved for execution, will not be permitted without the explicit approval of the SSC Director's office. Archival data should be used whenever possible to accomplish the science goals of any proposed investigation. Precisely what constitutes a duplicate observation is defined in the Spitzer Observing Rules document. For all the details see:

http://ssc.spitzer.caltech.edu/documents/rules/

To check for duplicate observations, we need to search the Spitzer Reserved Observations Catalog (or ROC, for short) ascii file or use Leopard to query the database. For more information on Leopard, see §2.3.

http://ssc.spitzer.caltech.edu/documents/leopard/

We recommend observers check their targets using Leopard rather than using the ROC. The ROC file is static, and reflects the state of our database at the instant we generated the ROC files. Leopard talks to our operational databases and thus reflects the real-time state of approved observations.