a>( 'CALENDAR', value )


   System
   -------

   You may set the system used for keeping time to be UTC (default)
   TDB (barycentric dynamical time) or TDT (terrestrial dynamical
   time). Both TDB and TDT have no leapseconds. As such the time
   elapsed between any two epochs on these calendars does not depend
   upon when leapseconds occur.

   To set the default time system, select TDT, TDB or UTC for value
   and make the following call.

      <a href="cspice_timdef_set.html">cspice_timdef_set</a>( 