A different approach is done via the setting withctisrcpos=Y: all event energy corrections do not use the actual RAWY coordinate but the corresponding RAWY location of the source (SRCPOS) as determined by the task epframes (either automatically or via setting withsrccoords=Y). So all events are assumed to originate from the source position. Events that really occur at a RAWY different from SRCPOS get a wrong (usually too high) CTI correction instead. (Note, that this procedure is the correct handling for TIMING and BURST mode - where it is performed automatically). A spatial selection should be applied in the final event analysis to deal only with detector portions dominated by Out-of-Time events. The task epchain may be used with the setting ccds=4 withctisrcpos=Y to process only the CCD 4 where usually the bright source is located that causes the Out-of-Time events.