XMM RPS Users' Manual

   
General considerations

1.

Choice of prime instrument

Users must first decide which is the main science goal and with which of the XMM science instruments this goal can be best achieved.

2.

Science mode of prime instrument

Next, the best-suited instrument mode with which to conduct the observations, depending on the target properties, must be chosen. More on this will follow in § 3.1.2, immediately below.

3.

Integration time

Then it must be decided how much integration time is needed for the prime instrument, operated in the selected mode, to achieve the science goals.

4.

Pointing direction

For extended targets the optimal pointing direction (which might not coincide with the catalogued target coordinates) must be chosen. The pointing should be chosen in such a way that the target is optimally located on the detector of the prime instrument. Thus, if there is a certain region, e.g., in an extended target that is of particular interest, the coordinates of that particular point should be chosen as the boresight coordinates.

5.

Avoidance of nearby sources

XMM science data (both X-ray and optical/UV) can be contaminated by radiation from nearby sources. In case that such exist and must be avoided, this might, e.g., lead to position angle constraints on the observations (for example in order to prevent spectral overlaps).

Users must check for the presence of bright optical/UV sources in the OM FOV. In case a source violates the OM brightness limits, which are listed in UHB Table 19 , OM observations may not be conducted and the instrument must be put in the ``GO-OFF'' mode of operation (blocked filter position).