Charles Mason

Mason's early career was spent at the Royal Greenwich Observatory near London. He served as assistant astronomer from 1756 to 1760 under the Reverend James Bradley, the third Astronomer Royal. While employed at the Greenwich Observatory, Mason became familiar with Professor Tobias Mayer's Tables of the Moon. The Lunar Tables were designed to solve the problem of determining longitude at sea, a challenge that frustrated scientists and navigators for decades. Mason worked throughout his life to perfect the Lunar Tables as a method of improving navigation at sea. In 1787, Mason's work was recognised, and he was awarded £750 (not the full prize of £10,000 to £20,000) by the Board of Longitude for his work on perfecting the Tables, that £750 being equal to £101,842 today. In 1761, Mason was assigned to travel to the island of Sumatra by the Royal Society to observe the transit of Venus as part of an international effort to record data that would enable scientists to determine the distance from the Earth to the Sun. Mason was joined by Jeremiah Dixon, a surveyor and amateur astronomer from Cockfield in the County of Durham.