If an extension had TSTART and TSTOP keywords, it checks to be sure that neither is zero and that TSTART <= TSTOP. It also sets the values for the DATE-OBS, TIME-OBS, DATE-END, TIME-END keywords. Finally it keeps a running tally of the earliest TSTART and the latest TSTOP. These values are used to mark start and finish of the entire observation.
Every TIME column is checked for whether it is in order. The BAT bcdh files are not checked since the BAT_TELEM column is not supposed to be in order.
Finally, for every GTI extension, the subroutine checks that no two GTIs overlap, that they are in order and that they all have STOP > START.
Parent Class: Subs::Sub