13. Time Series Observations

Repeated observations of (inertial) celestial objects that vary with time are becoming a popular request. For this next cookbook chapter, we use the real-life example found for the observations of TrES-1, from DDT program 227 (Charbonneau). The original AORs for this program can be viewed via Spot (choose ``View Program" and enter pid 227), or slightly relabeled and modified (for new slew model) AORs that are functionally the same can be downloaded as part of this cookbook. Because imaging with MIPS and IRAC have been covered thoroughly in earlier chapters (see §4, §5, §9 and §10), we will not spend as much time on those aspects of these observations here; this chapter is meant primarily to give an example of observing the same object repeatedly, and using Spot to tell Spitzer exactly how you want the observations carried out. We will plan an observation of the extra-solar planet TrES-1 during the time of secondary eclipse (when the planet passes behind the star). The science learned from these real-life observations is described in Charbonneau et al., 2005, ApJ, 626, 523. The secondary eclipse reveals two key quantities of the planet: its temperature (from the eclipse depth), and its orbital eccentricity (from the eclipse timing).