XMM-Newton Science Analysis System . attcalc (attcalc-4.32) [xmmsas_20060628_1801-7.0.0] . Meta Index . The task attcalc calculates linearized sky coordinates (i.e. a tangential projection on the sky) on an event-by-event basis, and stores these new coordinates in the input event list in columns X and Y , as offsets from a particular reference point. ... Input Files . Output Files . ... Index . XMM-Newton SOC/SSC -- 2006-06-28 ...