XMM-Newton Data Files Handbook

4.1.8 OM diagnostics files

Some ODFs may contain OM calibration files of the following types:

• Flat fields and dark frames with filename
  • *OM*IMI.FIT if obtained as full frame low resolution
  • *OM*E4I.FIT if obtained as full frame high resolution
  These files can be distinguished from normal science images only by the FILTER keyword in the fits file header. For calibration files, the OM filter wheel is in the blocked position (FILTER=1200).

• Intensifier and CCD characteristics (also called engineering 6). The names of these files are *OM*E6I.FIT, and they provide a characterisation of the detector response.

• Centroiding table confirmation (also called engineering 3 and 7). The names of these files are *OM*E3I.FIT and *OM*E7I.FIT, and they are used by the on-board and ground software to compute the look-up tables used in the pixel centroiding algorithm.

The OM diagnostics files can only be used with special software and are of no use to the general user.