The Royal Greenwich Observatory (RGO), a comprehensive Observatory built by King Charles II in Greenwich, London, in 1675, laid the foundation stone on August 10, and the King created the Royal Astronomer's post (the first was John & Franstein) to serve as the observatory's director and "dedicated to the most sincere governance of the observatory. Concern about and strive to correct the catalogue of celestial motion and the position of stars so as to correctly determine longitude and make navigation a perfect art. The Observatory is located on a hill overlooking the Thames River in London at Greenwich Park.