Flamsteed House in Greenwich Park London late th century Flamsteed House was designed by Christopher Wren on the orders of Charles II as a royal observatory At this time the problem of finding longitude at sea was unsolved and the observatory was built in the expectation that it would be possible to produce tables to enable mariners to plot their position The first nation to solve the problem would have naval and mercantile advantage John Flamsteed after whom the building is named was the first Astronomer Royal