XMM RPS Users' Manual

   
For timing observations

6.

Science mode of all instruments

For EPIC users must check that any neighbouring bright sources are not in the same CCD row/column as the desired object by selecting an appropriate position angle, if necessary, in order to avoid contamination of the target data.

If high time resolution is required, the RGS HIGH TIME RESOLUTION mode should be chosen (see UHB section on RGS modes ). Fastest readout (on part of the spectrum) is achieved if only one CCD is read out.

For each of the science instruments as prime there is one OM fast mode default configuration. The user should consider whether the time resolution of OM fast mode data is important for the observations and choose the time slice duration accordingly. In case of OM grism observations with a fast mode window on the zeroth order image, OM should be declared prime.

7.

Length of observation

If the observation is long compared with the visibility window (as reported by the online XMM Target Visibility Tool), the user must consider how best to split it up, e.g., into multiple observations that fit into continuous visibility periods. Other criteria for the split of an observation could be optimal filling of gaps between CCDs, or a calculation to fit in a certain sequence of OM filters observed with one of the OM default configurations (i.e., with exposure multiples of five per filter).

8.

Selection of EPIC optical blocking filter

Users must check the visible magnitude of in-field or nearby optical sources and the science target itself. If the soft X-ray response is important, one should choose the thinnest filter compatible with the brightest visible objects, as described in the UHB section on EPIC filters .

9.

RGS readout sequence

In case of HIGH TIME RESOLUTION mode observations it must be decided whether one or all nine CCDs shall be read out.

10.

Choice of OM filter sequence

For the OM it must be decided if specific filter coverage is necessary for the science or if the recommended filter sequence is adequate (see UHB section on OM default configurations ).

11.

Length of exposures

Telemetry and onboard memory limits place upper and lower boundaries on the duration of single OM exposures as listed in § 5.3.3.5.