4.5.2 Instrument and setup overheads
The following instrument and setup overheads apply to XMM-Newton science
observations. Note that some of them will occur simultaneously, at the
start of an observation.
- EPIC setup time is mainly due to the upload (in the case of the
MOS cameras) or the calculation and download (in the case of the pn
camera) of the offset tables needed to compute the amount of the optical
loading of the CCD chips, i.e., the charges that must be subtracted to
set the correct zero level for X-ray observations. The overhead of
each pn exposure is mode dependent and varies from
The overhead of each MOS exposure due to the offset table
upload is about 10 minutes.
- The overhead of RGS exposures is about one minute and a half.
- The overheads of the OM exposures are mainly due to the setup of
the instrument and the field acquisition driven by the guide star
recognition (cp. § 3.5.8).
Instrument and setup overheads need to be taken into account in
XMM-Newton observing proposals. A detailed description of the instrument
and setup overheads can be found in the XMM-Newton Proposers
Guide and Remote Proposal Submission Software Users Manual (XRPS).
An overview of overheads is given in the
European Space Agency - XMM-Newton Science Operations Centre