What Is the Greenwich Royal Observatory?

Lumara Lee

The Greenwich Royal Observatory located in Greenwich, England, has made great contributions to the fields of astronomy and navigation. King Charles II established the Greenwich Royal Observatory in 1675 and appointed the first Astronomer Royal, a position that has continued to the present day. The king told the first Astronomer Royal "to apply himself with the most exact care and diligence to the rectifying of the tables of the motions of the heavens, and the places of the fixed stars, so as to find out the so much desired longitude of places for the perfecting of the art of navigation." Since then, the observatory has performed this function, and more.

Sculpture on the Prime Meridian, near the Greenwich Observatory.
Sculpture on the Prime Meridian, near the Greenwich Observatory.

Two notable contributions made by the Greenwich Royal Observatory are the establishment of the prime meridian and the institution of Greenwich Mean Time (GMT), which took place concurrently. The prime meridian is the longitudinal line that encircles the earth and was designated as 0 degrees longitude in 1884. This line runs directly through one of the buildings on the site of the observatory. It has been estimated that there were at least 2,000 time zones before GMT was established as the international standard at the prime meridian. Today, a person can straddle that imaginary line in the Meridian Courtyard at the observatory and be standing in two different hemispheres.

Prime Meridian at the Royal Observatory in Greenwich, United Kingdom.
Prime Meridian at the Royal Observatory in Greenwich, United Kingdom.

The complex at Greenwich includes many edifices besides the observatory including the Meridian Building, Flamsteed House, the National Maritime Museum and the Queen’s house. Flamsteed House contains the apartments used through the centuries to house the Astronomer Royals and their families. It was also the first Greenwich Royal Observatory. In 1833, Flamsteed House made the news when a time ball was constructed on its roof. This time ball was designed to drop every day at precisely 1 p.m. GMT and has continued to do so for more than 150 years.

A global map including time zone divisions.
A global map including time zone divisions.

Visitors to the complex can visit view galleries filled with displays showing the formation of the universe, a history of timekeeping, photographs taken of deep space, and other stunning exhibits. The Greenwich complex also features a cutting-edge planetarium. Astronomers Royal at the observatory study the heavens with a 28-inch refracting telescope, one of the largest in the world. In 1997, the Greenwich Royal Observatory was designated a UNESCO World Heritage Site due to the advancements it has made in mankind's understanding of the universe. These include the first sightings of Uranus and the predicted return of Halley's comet.

The planet Uranus, a gas giant that orbits between Saturn and Neptune, was discovered at the Greenwich Royal Observatory.
The planet Uranus, a gas giant that orbits between Saturn and Neptune, was discovered at the Greenwich Royal Observatory.

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Discussion Comments


@jcraig - You are absolutely correct and I feel like there may not be a single facility of this kind in the world that can claim the type of history that it has or rival its contributions to human history.

I find it quite amazing that all this happened at this facility and on top of the two units of standardization that they created to be followed across the world, they also discovered a planet. I find this in itself to be absolutely amazing and feel like that next time I take a vacation to England it may be worth making a visit to this facility simply due to the rich history that it has.


It seems like the Greenwich Royal Observatory has a very rich history and has provided a very long lasting contribution to human history.

Not only did they set the standard of time zones, which is an achievement in itself, they are also the set prime meridian and came up with the concept of longitude and latitudes that ultimately decide how to determine locations in the world.

These two contributions are long lasting contributions to human history and are standardized all across the world.

What I also find very cool is that Greenwich discovered a planet, Uranus, at their facility which is also something that not very many observatories can claim.


@matthewc23 - You are absolutely correct. I have heard the story that it was an American creation as far as the concept of time zones goes, but I do not think that this is the case.

The Greenwich Royal Observatory standardized time for which everyone can follow and even figured out the perfect formula for adjusting the the daylight that was available in the area at certain times.

Although there are some discrepencies, such as the sun setting very late in some places, the time zones are more or less close to being exact in regards to day light and has proved to be a very good system they have set up.


Most people do not realize that there has not always been the standard time zones that there are today.

I have heard a story that they began the concept of time zones due to the times of trains and how people were missing trains by a few minutes simply because towns would be slightly different depending on what their interpretation of the time was.

The Greenwich Royal Observatory set the standard for which everyone could follow and centralize time allowing for less confusion and more efficiency as far as time is concerned.

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