Royal Observatory, Greenwich
At the Royal Observatory, Greenwich, time and place snap into focus. Stand astride the Prime Meridian, marked in 1851 and adopted worldwide in 1884, then meet Harrison's chronometers that solved longitude at sea. Flamsteed House frames London, while the 28-inch Great Equatorial Telescope broods under its green dome. Outside, the red time ball drops at one o'clock, a nineteenth-century signal still working. Planetarium shows add a cosmic coda. The hill is steep but rewarding; bring comfortable shoes and a camera for sunset across the Thames. Book a timed slot, allow 90-120 minutes, and fold in the Cutty Sark for a perfect Greenwich double.
Opening Hours
What's not to miss inside?
Prime Meridian Line
0° longitude starts hereSir George Airy marked the Meridian in 1851; it became the world’s reference at the 1884 conference.
📍 Flamsteed House courtyard
Harrison Timekeepers
Solved longitude at seaJohn Harrison’s H1-H4 chronometers (1730s-1759) slashed navigational errors and transformed ocean travel.
📍 Time galleries, Flamsteed House
Great Equatorial Telescope
Victorian 28-inch refractorInstalled in 1893, this giant refractor sits beneath the distinctive green ‘onion’ dome overlooking London.
📍 Onion-dome building
Shepherd Gate Clock
First public GMT clockMounted in 1852, its 24-hour dial displayed Greenwich Mean Time to Londoners decades before radio time signals.
📍 Outside main gate
Planetarium & View
Immersive shows and skylineOpened in 2007, the planetarium complements one of London’s finest vistas across Greenwich Park to Canary Wharf.
📍 Peter Harrison Planetarium / park terrace
Inspire your Friends
- Founded in 1675 by King Charles II, the observatory set standards for navigation and time.
- The Prime Meridian of 1851 was adopted internationally in 1884; over two-thirds of ships already used Greenwich charts.
- Greenwich’s red time ball has dropped almost daily at 13:00 since 1833 to signal the exact time to ships.
- Harrison’s H4 sea watch of 1759 demonstrated accuracy within seconds over an Atlantic voyage.
- The 28-inch refractor’s Great Equatorial Building dates from the late 19th century and remains a Greenwich landmark.
