Royal Observatory, Greenwich. Engraving of Flamsteed House, the main building of the Royal Observatory, Greenwich, London, England, seen from the north-east. The observatory was founded in 1675 with the building of Flamsteed House. It was the first purpose-built research institution in Britain, and for centuries was the centre of astronomical and meteorological research in the UK. On top of the east turret of the main observatory building is a time ball, a device used to indicate a set time of day. At that time, usually 1pm, the ball was dropped, allowing those within viewing distance to set their clocks. This artwork is based on a photo by the British meteorologist James Glaisher (1809-1903).