Old Greenwich Royal
TfL Fare Zone 2
This historic collection of 17th century buildings, designed by Sir Christopher Wren, is now part of the Royal Museums in Greenwich. The Royal Observatory is one of the four Royal Museums in Greenwich. There are three museums in Greenwich Park – the National Maritime Museum (NMM) The Queen's House, the Old Greenwich Royal Observatory itself and in Cutty Sark Gardens near Greenwich Pier the famous Cutty Sark Sailing Clipper.
It is the home of the Prime Meridian (0° of Longitude) and Greenwich Mean Time.
Not only did the first Astronomer Royal, John Flamsteed live and work here, so did Edmund Halley, discoverer of the famous comet named after him and also Sir Isaac Newton.
The time ball still drops from the mast on the Observatory roof each day at 13:00 and the Greenwich Atomic Clock generates the exact time used in Universal Co-ordinated Time (UTC).
Note: Entrance charges apply to the Meridian Courtyard and Flamsteed House, including the Time galleries (ages 5 and under go free).
As the visitor enters the courtyard, negotiating the many tourists straddling the brass Meridian line set in the cobbles, they will see in front of them the oldest of the buildings, Flamsteed House. This is where John Flamsteed lived and worked in 1675. There are a couple of steps up into the building so it is not suitable for wheelchair bound visitors. The four rooms on the ground floor were his living quarters and are furnished appropriately. Upstairs is the Octagon Room where he worked until his death in 1719.
In the Octagon Room are the famous John Harrison marine timekeepers with which he tried to solve the longitude problem. Also on display are all manner of astronomical navigational instruments going back to the 13th century, and telescopes belonging to Flamsteed, Halley and Airy.
We take the imaginary lines of longitude we see drawn on a globe for granted, but in the 17th century longitude could not be accurately calculated. Sailors who could not calculate their position accurately were in grave danger of shipwreck. King Charles II established the Observatory at Greenwich to establish a means of fixing longitude.
It was discovered that if one compared the time shown on two clocks, one adjusted to keep showing local time and the other remaining unaltered, the longitude could be calculated. 15° of longitude equated to one hour of time. The problem was that it was almost impossible to maintain a clock’s accuracy at sea due to the movement of the ship. An error of just a few minutes could lead to disaster.
John Harrison was a humble Lincolnshire joiner who started making wooden clocks. A national competition to solve the longitude problem promised rich rewards for the first person to invent a timepiece that could perform accurately at sea with only a minute margin of error (2 minutes).
Harrison invented a pocket watch with an error rate of only 39.2 seconds over a 47 day voyage! Harrison solved the problem and Captain James Cook took a copy of one of his watches around the world and it only showed a maximum variation of 8 seconds, no matter if he was in polar or tropic waters.
As a result and with international agreement, Greenwich Observatory was made the Prime Meridian (0° longitude). Greenwich Mean Time (GMT) is mean solar time, with midday defined as the time at which the sun crosses the Greenwich Meridian. The Prime Meridian passes through the Meridian Building (which is really three buildings built between 1749 and 1855).
The time ball on the roof of Flamsteed House was erected in 1823 and provided the first public time signal. It could be clearly seen by shipping moored in the River Thames and it was used as a time check. Every day the ball is raised to the top of the pole and reaches the top at 2 minutes to 13:00 hours. At exactly 13:00 it is dropped. If you blink you will miss it!
There is also a ‘camera obscura’ in a building beside Flamsteed House.
The Museum collection holds many interesting time distribution pieces including the original regulators generating the BBC’s ‘six pip’ time signals. The items are displayed throughout the Observatory’s buildings.
There is level access to the courtyard and Meridian Line, the display of transit instruments and the gift shop.
Flamsteed House Octagon Room is not accessible.
Flamsteed House Octagon Room is not accessible.
Open all year except 24-26 December.
10:00 – 17:00 hours. Last admission is 30 minutes before closing.
Entrance to the Astronomy Centre is free.
Entrance charges apply to the Meridian Line and Flamsteed House. Save with a Combo Ticket. Find out more at Web: Royal Observatory/ Tickets & Prices
A Walk to The Observatory
It is quite a climb up the hill to the Observatory, but is well worth it. There are two ways to walk up – either by taking the well signed walking path through the park and then climbing the very steep stairs to the top (the quickest route).
Then there is the motor vehicle free road - (The Avenue) from St Mary’s Gate which climbs the hill in an anti clockwise direction and reaches the Observatory after passing the ‘Royal Park Pavilion Tea House’ – a welcome break for those with a slower pace!
Contact & Further Information
+44 (0) 2088 584 422
+44 (0)2083 126 565 - Recorded information
TfL Fare Zone 2 Transport for London Journey Planner
See ‘Greenwich Getting There’ directions on the Royal Observatory website (link above). Follow the Tourist Information signs in Cutty Sark Gardens and in Greenwich itself.
Google Maps - Royal Observatory Greenwich