Visiting the Greenwich Observatory: Time to Learn About Time

greenwich royal observatory
by Anisa // 34 Comments

You may not have heard of the Greenwich Royal Observatory, but the research done there impacts your life on a daily basis.  It’s the home of the Prime Meridian and Greenwich Mean Time (GMT).  This topic had never really piqued my interest before, but being at the observatory and learning about the history was fascinating.  And kids will love the planetarium.  

The Observatory is part of Greenwich Maritime which made the very exclusive list of UNESCO World Heritage Sites.  If that is not enough to convince you, the Greenwich Observatory has one of the best views of London.

The Royal Greenwich Observatory needs to be on your list for London.  Let me tell you more about what there is to see there and why you must visit.

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View of the Royal Greenwich Observatory from Greenwich Park.
View of the Royal Greenwich Observatory from Greenwich Park.

Our Visit to the Greenwich Royal Observatory

I didn’t know much about what to expect at the Greenwich Royal Observatory except that we would see the Prime Meridian. Right after you get your ticket to the London observatory, you will see a sign marking Flamsteed’s Meridian Line on the wall.  This was the first Meridian line and there was even another one before the Prime Meridian Line we use today was established.  


The Prime Meridian

The Prime Meridian divides the earth into two hemispheres, Eastern and Western similar to how the Equator marks the line between the Northern and Southern Hemispheres.  The Prime Meridian is the 0 degree line for Longitude and the Equator is the 0 degree line for latitude.

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Like everyone else, we had to get our pictures with one foot on either side of the Greenwich Meridian line, standing in both the Eastern and Western Hemispheres.   While the Prime Meridian is supposed to be 0 degrees longitude the 0 degree point for your GPS is about 100 meters east because of the Earth’s slightly irregular shape.

Anisa standing over the Prime Meridian at the Royal Greenwich Observatory. One foot in the Eastern Hemisphere and one foot in the Western Hemisphere.
Anisa standing over the Prime Meridian. One foot in the Eastern Hemisphere and one foot in the Western Hemisphere.

Camera Obscura

Next, we checked out the camera obscura.  It is a darkened room with a pinhole that uses a mirror and lens to project an image.  Originally it was used to study the sun, but now it projects a live image of the Queen’s House.  The Queen’s House was supposedly a gift from King James I to Queen Anne of Denmark to apologize for swearing in front of her after she had accidentally killed one of his favorite dogs during a hunt.  

The building is important architecturally (first fully classical building in England), and famous for its former occupants (legends say there is a ghost) and art collection.  When you enter the camera obscura room, take a moment to let your eyes adjust to the darkness.  Then take a close look at the image.  We could see people and cars moving.  

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The image of the Queen's House from the Camera Obscura at the Greenwich Royal Observatory. It's like watching an old black and white video.
The image of the Queen’s House from the Camera Obscura. It’s like watching an old black and white movie.

Flamsteed House

Then we visited the Flamsteed House.  This is where the Royal Astronomers and their families lived.  Upstairs is the Octagon Room which was designed by Christopher Wren, the architect that designed St. Paul’s and also the Naval Academy in Greenwich.  I was impressed with the trim and the ceiling. You could also see some original clocks and mock ups of telescopes and accessories.

The exhibits downstairs did a great job explaining why time and the Meridian line are tied to the Observatory.  There was a big problem with shipwrecks because it was hard to know where you were in the sea.   You could determine your latitude by using the location of the sun at noon, but longitude is not as simple and even more difficult when at sea.  You could measure how long you were gone and use that to help you determine how far you had traveled.

However, there were two issues with that method – first, factors like wind and current could affect your speed and second, the clocks used during that time were pendulum ones, which could not keep accurate time on a swaying boat.  One reason the Royal Observatory was established in 1675 was to solve this “Longitude Problem.”   After several attempts, John Harrison created a mechanical clock that would work effectively at sea.

Harrison's fourth timekeeper, which finally proved that the timekeeper method of finding longitude was practical - on exhibit at the Greenwich Observatory.
Harrison’s fourth timekeeper, which finally proved that the timekeeper method of finding longitude was practical.

Greenwich Mean Time and the Ball Ceremony

Longitude is connected directly with time because the Earth is divided vertically into time zones.  So you can compare the time at your current location to a fixed point to determine your longitude.  

In 1884, the international community agreed that the Greenwich Meridian (Prime Meridian) would be that point and also established Greenwich Mean Time (GMT).  All time zones would be calculated from GMT.  You will notice the Greenwich Observatory clock on the gate showing GMT, known as the Shepherd Gate Clock, but it is actually controlled by a master clock inside the main building. 

In order to help ensure everyone was keeping to the correct time, in 1833 the Greenwich Royal Observatory implemented a ceremony where a red ball on a pole on top of the Flamsteed House drops to signify 1 pm.  This ceremony still takes place today, as you can see in the video.

A little before 1 pm, we went to the courtyard to watch the Greenwich time ball drop.  Just like clockwork, five minutes before the hour it started to rise up, and then two minutes to the hour reached the top.  Then at 1 pm, it dropped.  

Of course, living in NYC, this reminded me of the ball in Times Square on New Year’s Eve.  I wonder if the idea for that ball came from the Greenwich Royal Observatory?

Meridian Observatory

Inside the Meridian Observatory, you get to see some of the telescopes the Royal Astronomers used.  I was pretty impressed with these until I saw the Great Equatorial Telescope.  You climb up a spiral staircase and then you will see it.  It pretty much takes up the whole dome.  

We timed it perfectly so that we could hear about the telescope and get a demonstration.  The Greenwich Observatory telescope is over 100 years old, yet it is still the best lens telescope in England.  They showed some of the images it captured on tv screens while the presenter showed how the telescope could move.  The most impressive part is that the dome rotates so that you could have the opening wherever it was needed.  As Russell said there was something very James Bondish to it.  

Greenwich Planetarium

Then it was time for our Planetarium Show – Asteroid: Mission Extreme.  It was open seating and we sat in the middle of the second row.  It might have been better if we were further back but those seats fill up fast.  The seats were almost too comfortable.  The movie was fun, and you definitely feel like you were moving.  After the movie, we checked out the exhibits at the Planetarium, which were all very interactive and kid-friendly.

Russell with an asteroid on display at the Planetarium at the Greenwich Royal Observatory. It is about 4.5 billion years old.
Russell with an asteroid on display at the Planetarium. It is about 4.5 billion years old.

Greenwich Observatory Tickets

The Royal Greenwich Observatory offers several different ticket options, but to get the best prices you will want to make your purchase online

You can also purchase a combined ticket for the MBNA Thames Clipper and the Greenwich Observatory and arrive by boat.  For those over 60, you can get one third off entry to the main attractions and tours on Tuesdays.  If you plan to visit the Observatory often, you may want to consider becoming a member.

You will need to buy your tickets to the Planetarium shows separately.  These shows are free for members but still need to be book.  The planetarium is popular, so get tickets for the show you want to see in advance.  It’s best to book online as soon as you know you are going to Greenwich or worst case, you can try first thing when you get to the British Royal Observatory as sometimes there are cancellations.

Note: Some of the other attractions in Greenwich, like the Queen’s House and the National Maritime Museum are free!

Greenwich Observatory Opening Hours

The Greenwich Observatory is open daily from 10 am to 5 pm.  The last entry is 4:30 pm.  Please note that the Observatory is closed December 24th-26th.

How to Get to the Greenwich Observatory

Greenwich is a borough in southeast London that is accessible by DLR (part of the London Underground i.e. Tube) using the Greenwich Cutty Sark stop.  You can also take the MBNA Thames Clipper.  The National Maritime Museum has limited parking available for £15 the day.    You can easily spend a whole day as there are many things to do in Greenwich.

We got lucky with the perfect weather the day we visited, so I enjoyed the walk from our car to the Observatory.  The last bit was pretty steep, but those views are worth it.  

It was a little foggy when we first arrived, but when that cleared later in the day we could see all the way to St. Paul’s.  The grass in this park is also some of the greenest I have ever seen.  We saw lots of picnickers enjoying it.

View from the hill by the Royal Greenwich Observatory. You can see the Queen's House, Canary Wharf, and the O2 (to the right).
View from the hill by the Royal Greenwich Observatory. You can see the Queen’s House, Canary Wharf, and the O2 (to the right).

Is Visiting the Greenwich Observatory Worth it?

Yes, I enjoyed my time in Greenwich and my visit to the Royal Greenwich Observatory.  Additionally, I definitely learned some great trivia facts.  Plus, I got my picture with the Prime Meridian – that’s priceless! Both kids and adults will have a good time, and it’s actually easier than you would expect to get to Greenwich from Central London.

Greenwich has so much to see, so I hope to visit again and see the Cutty Sark, the O2, Queen’s House, and Maritime Museum.  

Have you been to Greenwich?

I would love to hear about your experience.


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Expert Tips for Visiting the Royal Greenwich Observatory

  • Buy your Royal Observatory tickets online and consider getting one of the package options to save money.
  • There is no specific Greenwich Observatory parking, but you can park in the lot for the Maritime Museum.
  • An audio guide comes with your admission ticket.  You can pick it up in the courtyard right outside the ticket lobby.
  • Be sure to catch the Greenwich time ball drop at 1 pm GMT.
  • Try to catch the talk about the Great Equatorial Telescope, so that you can see the demonstration.
  • Get your tickets for the Planetarium in advance and try to sit towards the back of the theater.

Disclosure: No financial compensation was received, but the Greenwich Royal Observatory did provide complimentary tickets. As always, opinions expressed here are my own.

This post also contains affiliate links. This means we will receive a small commission for some purchases made using links in our blog with no additional cost to you. Please be assured we would not promote any product unless we believe that our readers will also benefit. The commission does not influence the editorial content of this site.


Last Updated on December 7, 2021

About the Author

Anisa is an experienced international traveler with extra pages in her passport and stamps from 41 different countries across 5 continents (and counting). She was born and raised in Texas. After a 13 year stint in NYC, she moved to England to live with her husband.