The meta-task eimageget allows a convenient creation of a set of images for one EPIC (pn or MOS) exposure. For individual energy bands, the task creates images of the observation, scaled out-of-time (OOT) images (EPIC-pn only), scaled filter-wheel-closed (FWC) images and vignetting corrected exposure maps and one mask (see Fig. 1). These images can be used to create background-subtracted and vignetting-corrected images latter on.
The OOT images are scaled according to the science mode of the exposure and can be subtracted from the observation images. The FWC images are scaled to have the same count rate in the shielded detector corners. Focused X-rays cannot reach these corners, thus events are basically caused by the detector background. After a subtraction of the detector background, which has a rather flat profile, the images can be corrected for vignetting using the exposure maps. Vignetting affects all X-rays that are focused by the telescopes, including e.g. the cosmic X-ray background or solar-wind charge exchange. Note, that the flaring detector background, caused by soft protons, shows some vignetting and should be removed by using a temporal filtering beforehand.