Royal Observatory Greenwich

The Royal Observatory Greenwich is the centre of Britain's astronomical history. For nearly 400 years, it has been at the forefront of space study, and stands on the Prime Meridian - the centre of the planet. Located in the heart of London, this iconic institution is a branch of the Royal Observatory London, offering a rich blend of history, science, and spectacular views.

Enjoy access to Royal Greenwich Observatory with The London Pass®

• Pay nothing at the door, simply show your pass.
• Learn about how time was standardised, how the first telescope was made, and how science has changed through the ages.
• Free audio guide available in English, simplified English (great for kids or those learning the language), French, German, Spanish, Italian, Brazilian Portuguese, Russian, Chinese, Japanese and Korean.

Discover the past, present and future wonders of astronomy at the Greenwich Observatory—the centre of time. Take a fascinating journey through the historic home of British astronomy, Greenwich Mean Time, and the Prime Meridian of the World.

Please note: During busy periods, all visitors may still need to queue. 

Royal Observatory Greenwich history

As Europeans took to the seas to explore the world and trade with other countries, astronomical information was needed to make journeys safer. That's why, in the 17th Century, King Charles II appointed a Royal Commission to look into investing in astronomy. Among those sitting on the Royal Commission was Sir Christopher Wren, a former professor of astronomy at Oxford, now best-known for his architectural work. In 1675, the Commission reported back to Charles II, recommending the foundation of an observatory, Britain’s first state-funded scientific institution. That very day, plans were set in motion. John Flamsteed was named ‘astronomical observator’, and a new era for astronomy, time, and navigation had begun.

Wren suggested using the ruined Greenwich Castle as the site for the new observatory and designed the building. The site had the advantage of being on higher ground, and already had solid foundations. The first building, Flamsteed House, was built in less than a year, and cost just over £500. Flamsteed spent 40 years there, making over 50,000 observations of the moon and stars. Flamsteed and Edmond Halley, the first two astronomical observators, plotted every star visible in the north and southern hemispheres. Their work was key in helping to develop the first accurate clocks.

Up until the late 1800s, there were no measurements of time that were consistent both nationally and internationally. And in a world becoming more globalised every day from the construction of railways and international shipping lanes, an international time standard was vital.

That's why, in 1884, the International Meridian Conference was called, and Greenwich successfully became the Prime Meridian of the World.
 

Greenwich Observatory highlights

• Stand astride the world-famous Meridian Line, with one foot in the east and the other in the west.
• Learn about how great scientists first mapped the seas and the stars and stand astride two hemispheres on the Prime Meridian Line.
• See pioneering inventions and the UK’s largest refracting telescope. Touch a 4.5 billion-year-old asteroid.
• Enjoy breath-taking views across the whole of London.

Greenwich Royal Observatory Facts

• A bright red Time Ball sits on top of Flamsteed House. The ball rises to the top of its mast each day, beginning its ascent at 12.55pm, before dropping at exactly 1pm. Considered one of the earliest public time signaling devices in the world, it first dropped in 1833.
• The Royal Observatory Greenwich has a large collection of interesting clocks. Particular highlights include the Russian F.M. Fedchenko pendulum clock, which is said to be one of the most accurate timepieces on the planet. And the Shepherd Gate Clock mounted on the outer wall of the Observatory, which has an unusual 24-hour display
• The Prime Meridian goes right down the centre of the planet, at least as far as time is concerned. That means you can literally stand in the middle of the Earth.