The file may contain one or several image planes, where each plane harbours events within a certain energy band. The number of planes is given by the keyword NBAND, the energy range (a lower an upper limit, in WFC-channel numbers) is listed in BANDn (1 <= n <= NBAND).
The total time over which the image was taken, is given by the keywords TSTART and TEND. If this interval contains one or more gaps, the detector- image file has an extension named 'GTI', listing the start and end times of all 'good' intervals.
Pointing.
Binning. Depending on used instrument data file. X and Y event coordinates, format depends on Stage I processing
Simulation keywords.