Why was "tantrum" trending last week?
Plural ephemerides (ěf'ə-měr'ə-dēz')
A table giving the coordinates of a celestial body at specific times during a given period. Ephemerides can be used by navigators to determine their longitude while at sea and by astronomers in following objects such as comets. The use of computers has allowed modern ephemerides to determine celestial positions with far greater accuracy than in earlier publications.