Astronomer Royal is a senior post in the Royal Households of the United Kingdom. There are two officers, the senior being the astronomer royal dating from 22 June 1675; the junior is the astronomer royal for Scotland dating from 1834. The Astronomer Royal works to make observations to improve navigation, cartography, instrument design, and applications of geomagnetism. The position was created with the overall goal of discovering a way to determine longitude at sea when out of sight of land.