Different components of instrumentation for A1795 observation 0723802101 for pn (red lines), MOS1 (black lines), and MOS2 (blue lines). The top-left panel shows the total effective area generated with arfgen (solid lines; for clarity, MOS1 is not shown). The dotted lines indicate the average correction to the effective area assuming that the other instrument is perfectly calibrated (see Sect. 6). The other panels show the mirror-only effective area (top right), the QE of the detector (bottom left), and the transmission of the optical filter (bottom right).