John Flamsteed FRS (1648-1719) English astronomer, was appointed the first Astronomer Royal by Charles ll in 1675 on the founding for navigational purposes of the Royal Observatory Greenwich. As Britain's first state-funded scientific institution its objective was to investigate the possibility of finding longitude at sea by astronomical means. Over the next forty years, Flamsteed made over 50, 000 moon and stellar positional observations. These formed the basis of the first Greenwich star-catalogue Historia Coelestis Britannicus (3000 stars) and the Atlas Coelestis. Data collected at the Royal Observatory by Flamsteed was used by Isaac Newton to verify his theory of gravity. Though renowned for the accuracy of his calculations, he was a perfectionist and not an easy man to get on with, frequently in dispute with Isaac Newton and the astronomer Edmond Halley.