Name of the source-list file (OBSMLI), which will be modified by this task. Name of the external catalogue FITS data set to read. Minimum number of good X-ray detections in the input dataset. Minimum overall goodness-of-fit for updating of RA_CORR and DEC_CORR. Maximum resulting offset in arc-seconds. Systematic positional error component in arc-seconds. Maximum positional offset error for fitted position in arc-seconds. If yes will apply astrometric plate-scale correction to input positions