Royal Observatory

The site at the top of Greenwich Park was the original site of Greenwich Castle. The ruins left solid foundations and its placement at the top of the park provided an ideal location for Flamsteed House. This was the first part of the Observatory to be built. Commissioned by Charles II, it was Christopher Wren who both suggested the site and over saw the design. The building was intended to be a home for the Astronomer Royal and in July 1676, the first Astronomer Royal, John Flamsteed moved in. He held this position for 42 years, and since his appointment there have only been 9 Astronomers Royal. The house would later bear his name. During the next 40 years over 50,000 observations of the moon and stars were made and the house itself was extended to accommodate bigger instruments. 

The current Observatory holds the Great Equatorial Telescope, the largest of its kind in the UK and seventh largest in the world. Originally built to research double star systems, it remained in use until the late 1960's. However, due to the introduction of technology its use dwindled but is still used for observing the night sky. The dome housing the telescope is now fibreglass but was originally made from papier mache!

You will also notice the red time ball that sits on the roof of the Observatory. This ball is raised half way up the pole at precisely 12:55pm each day. At exactly 12:57 it is raised further up to the top and then dropped at 13:00. This was so the ships on the Thames could set their chronological clocks to the same time. This first public time signal was first sent in 1833.

Also on the site sits London’s only planetarium. This is housed inside a 45-ton bronze clad dome, with the north side tilted horizontally to 51.5º (the latitude of Greenwich) and the south side pointing at 90º to the local horizon. The top is slanted to be parallel to the celestial equator. Here, you can watch planetarium shows projected above your head and listen to Royal Observatory astronomers and scientists discuss journeys into space.