Split Exposures into Smaller Segments: New Monitor Preference
Proposer Threads (Cycle 19)
There are several occasions when splitting an exposure into shorter segments will enhance the science return of an observation but is not required to achieve core science goals. A prime example is a long exposure of a galaxy to characterize X-ray binary sources. If the exposure is split it becomes possible to search for source variability, but a split is not critical.
In Cycle 19 is now possible to express a preference for an exposure to be split. This is technically called a "monitor preference" because more than one visit to a source is defined as a monitor. Proposers who wish to request this option should should answer the question "Do you want more than one observation of this target?" with "Preferred, I have a preference for this target to be split" and fill in the monitor table giving exposure times and intervals between observations.
Targets without any user-imposed constraints will be scheduled at the time of the year when the pitch angle is cold to avoid thermal stress to the spacecraft. Splitting an exposure may mean some segments are moved out of the "cold pitch" zone. As with all preferences (see the CfP for more information), the requested split will be made on a best-effort basis and some segments might be observed back-to-back (no split) to manage the thermal profile of the spacecraft. Proposers whose science requires multiple observations of the same source should request a constraint.