To ease the use of the OM and to maximize the scientific yield of observations in cases when no particular instrument configuration is requested, OM default configurations have been defined. There is one type of default configuration per OM observing mode, thus one for the imaging mode and one for the Image plus Fast mode (§ 3.5.3.1). Default windows have also been predefined for the V and UV grisms exposures. Moreover, two additional full frame modes are available which allow imaging observation of the whole OM field of view.
The default configurations are as follows:
An example of the configuration corresponding to this mode is shown in Fig 85.
It is possible to obtain images of the whole OM field of view in full (high) or 22 binned (low) resolution. These modes do not allow tracking, and have higher instrumental overheads than the Imaging Mode default. However, they allow an homogeneous sampling of the whole OM field of view. They are therefore particularly well suited for survey studies, or to obtain multiobject grism spectroscopy in a wide field. These modes have a single window, no other window can be defined (either in image or Fast mode) within the same exposure. Along an observation Full-Frame imaging modes can be combined with exposure in modes requiring Field Acquisition (FAQ), but this can be done if and only if the Full-Frame exposure is performed after all the exposures which need FAQ (see § 3.5.7), because Full-Frame modes annihilate the results of FAQ.
The lack of tracking in Full Frame mode does not affect the quality of the image because, as experience has shown us, the drift of the XMM-Newton spacecraft is almost negligible (less than one arc sec per hour)
Two standard configurations are available for a user interested in using OM optical or UV grisms:
In addition to these default configurations it is also possible for OM users to define customized windows using the Science User Defined mode (see § 3.5.10.1).
Apart from the configuration of the OM exposures, users have to specify their choice of filter(s) and exposure times.