The Connaissance des temps (English: Knowledge of Time) is an official yearly publication of astronomical ephemerides in France. Until just after the French Revolution, the title appeared as Connoissance des temps, and for several years afterwards also as Connaissance des tems.
Since 1984 it has appeared under the title Ephémérides astronomiques: Annuaire du Bureau des longitudes.
Connaissance des temps is the oldest such publication in the world, published without interruption since 1679 (originally named La Connoissance des Temps ou calendrier et éphémérides du lever & coucher du Soleil, de la Lune & des autres planètes), when the astronomer Jean Picard (1620-1682) obtained from the King the right to create the annual publication. The first eight editors were:
Other notable astronomers who edited the Connaissance des temps were:
The volumes of the Connaissance des temps had two parts: