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Astronomers have been tasked with computing accurate ephemerides, originally for purposes of sea navigation, from at least the 18th century. In England, Charles II founded the Royal Observatory in 1675, which began publishing "The Nautical Almanac" in 1766. In France, the "Bureau des Longitudes" was founded in 1795 to publish the "Connaissance des Temps". The early fundamental ephemerides of these publications came from many different sources and authors as the science of celestial mechanics matured.