The Collaborative International Dictionary of English v.0.48:

Calippic \Ca*lip"pic\, a.
   Of or pertaining to Calippus, an Athenian astronomer.
   [1913 Webster]

   Calippic period, a period of seventy-six years, proposed by
      Calippus, as an improvement on the Metonic cycle, since
      the 6940 days of the Metonic cycle exceeded 19 years by
      about a quarter of a day, and exceeded 235 lunations by
      something more.
      [1913 Webster]