Royal Observatory, Greenwich
Overview
 
The Royal Observatory, Greenwich (formerly the Royal Greenwich Observatory or RGO), in London, England played a major role in the history of astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 and navigation
Navigation
Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...

, and is best known as the location of the prime meridian
Prime Meridian
The Prime Meridian is the meridian at which the longitude is defined to be 0°.The Prime Meridian and its opposite the 180th meridian , which the International Date Line generally follows, form a great circle that divides the Earth into the Eastern and Western Hemispheres.An international...

. It is situated on a hill in Greenwich Park
Greenwich Park
Greenwich Park is a former hunting park in Greenwich and one of the largest single green spaces in south east London. One of the Royal Parks of London, and the first to be enclosed , it covers , and is part of the Greenwich World Heritage Site. It commands fine views over the River Thames, Isle of...

, overlooking the River Thames
River Thames
The River Thames flows through southern England. It is the longest river entirely in England and the second longest in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford,...

.

The observatory was commissioned in 1675 by King Charles II
Charles II of England
Charles II was monarch of the three kingdoms of England, Scotland, and Ireland.Charles II's father, King Charles I, was executed at Whitehall on 30 January 1649, at the climax of the English Civil War...

, with the foundation stone being laid on 10 August. At this time the king also created the position of Astronomer Royal
Astronomer Royal
Astronomer Royal is a senior post in the Royal Household of the Sovereign of the United Kingdom. There are two officers, the senior being the Astronomer Royal dating from 22 June 1675; the second is the Astronomer Royal for Scotland dating from 1834....

 (initially filled by John Flamsteed
John Flamsteed
Sir John Flamsteed FRS was an English astronomer and the first Astronomer Royal. He catalogued over 3000 stars.- Life :Flamsteed was born in Denby, Derbyshire, England, the only son of Stephen Flamsteed...

), to serve as the director of the observatory and 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." The building was completed in the summer of 1676.
Unanswered Questions
Encyclopedia
The Royal Observatory, Greenwich (formerly the Royal Greenwich Observatory or RGO), in London, England played a major role in the history of astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 and navigation
Navigation
Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...

, and is best known as the location of the prime meridian
Prime Meridian
The Prime Meridian is the meridian at which the longitude is defined to be 0°.The Prime Meridian and its opposite the 180th meridian , which the International Date Line generally follows, form a great circle that divides the Earth into the Eastern and Western Hemispheres.An international...

. It is situated on a hill in Greenwich Park
Greenwich Park
Greenwich Park is a former hunting park in Greenwich and one of the largest single green spaces in south east London. One of the Royal Parks of London, and the first to be enclosed , it covers , and is part of the Greenwich World Heritage Site. It commands fine views over the River Thames, Isle of...

, overlooking the River Thames
River Thames
The River Thames flows through southern England. It is the longest river entirely in England and the second longest in the United Kingdom. While it is best known because its lower reaches flow through central London, the river flows alongside several other towns and cities, including Oxford,...

.

The observatory was commissioned in 1675 by King Charles II
Charles II of England
Charles II was monarch of the three kingdoms of England, Scotland, and Ireland.Charles II's father, King Charles I, was executed at Whitehall on 30 January 1649, at the climax of the English Civil War...

, with the foundation stone being laid on 10 August. At this time the king also created the position of Astronomer Royal
Astronomer Royal
Astronomer Royal is a senior post in the Royal Household of the Sovereign of the United Kingdom. There are two officers, the senior being the Astronomer Royal dating from 22 June 1675; the second is the Astronomer Royal for Scotland dating from 1834....

 (initially filled by John Flamsteed
John Flamsteed
Sir John Flamsteed FRS was an English astronomer and the first Astronomer Royal. He catalogued over 3000 stars.- Life :Flamsteed was born in Denby, Derbyshire, England, the only son of Stephen Flamsteed...

), to serve as the director of the observatory and 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." The building was completed in the summer of 1676. The building was often given the title "Flamsteed House".

The scientific work of the observatory was relocated elsewhere in stages in the first half of the 20th century, and the Greenwich site is now maintained as a tourist attraction.

History

There had been significant buildings on this land since the reign of Edward I. Greenwich Palace, next to the site of the present-day Observatory was the birthplace of Henry VIII and the Tudors used Greenwich Castle
Greenwich Castle
Greenwich Castle was a castle used during the reign of Henry VIII, located in Greenwich Park, in Greenwich, England. The Royal Observatory, Greenwich now stands on the land. Greenwich Castle was apparently a favourite place for Henry VIII to house his mistresses, as it was within easy travelling...

, which was built on the land that the Observatory now stands on. Greenwich Castle was apparently a favourite place for Henry VIII to house his mistresses, so that he could easily travel from the Palace to see them.

The establishment of a Royal Observatory was proposed in 1674 by Sir Jonas Moore
Jonas Moore
Sir Jonas Moore, FRS was an English mathematician, surveyor, Ordnance Officer and patron of astronomy. He participated in two of the most ambitious English civil engineering projects of the 17th century: the draining of the Great Level of the Fens and the building of the Mole at Tangier...

 who, in his role as Surveyor General at the Ordnance Office, persuaded King Charles II that the Observatory might be built with Flamsteed employed in it. The Ordnance Office was given responsibility for building the Observatory, with Moore providing the key instruments and equipment for the observatory at his own personal cost. Flamsteed House, the original part of the Observatory, was designed by Sir Christopher Wren
Christopher Wren
Sir Christopher Wren FRS is one of the most highly acclaimed English architects in history.He used to be accorded responsibility for rebuilding 51 churches in the City of London after the Great Fire in 1666, including his masterpiece, St. Paul's Cathedral, on Ludgate Hill, completed in 1710...

 probably with the assistance of Robert Hooke
Robert Hooke
Robert Hooke FRS was an English natural philosopher, architect and polymath.His adult life comprised three distinct periods: as a scientific inquirer lacking money; achieving great wealth and standing through his reputation for hard work and scrupulous honesty following the great fire of 1666, but...

 and was the first purpose-built scientific research facility in Britain. It was built for a cost of £520 (£20 over budget) out of largely recycled materials on the foundations of Duke Humphrey's Tower, which resulted in the alignment being 13 degrees away from true North, somewhat to Flamsteed's chagrin.

It not only housed the scientific instruments to be used by Flamsteed in his work on stellar tables, but over time also incorporated a number of additional responsibilities such as the keeping of time and later Her Majesty's Nautical Almanac Office.

Moore donated two clocks, built by Thomas Tompion
Thomas Tompion
Thomas Tompion was an English clock maker, watchmaker and mechanician who is still regarded to this day as the Father of English Clockmaking. Tompion's work includes some of the most historic and important clocks and watches in the world and can command very high prices whenever outstanding...

, which were installed in the 20 foot high Octagon Room, the principal room of the building. They were of unusual design, each with a pendulum 13 feet (3.96 metres) in length mounted above the clock face, giving a period of four seconds and an accuracy, then unparalleled, of seven seconds per day.

Prime Meridian

British astronomers have long used the Royal Observatory as a basis for measurement: four separate meridians have been drawn through the building. The basis of longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....

, the Prime Meridian
Prime Meridian
The Prime Meridian is the meridian at which the longitude is defined to be 0°.The Prime Meridian and its opposite the 180th meridian , which the International Date Line generally follows, form a great circle that divides the Earth into the Eastern and Western Hemispheres.An international...

, established in 1851 and adopted at an international conference in 1884, passes through the Airy
George Biddell Airy
Sir George Biddell Airy PRS KCB was an English mathematician and astronomer, Astronomer Royal from 1835 to 1881...

 transit circle
Meridian circle
The meridian circle, transit circle, or transit telescope is an instrument for observing the time of stars passing the meridian, at the same time measuring its angular distance from the zenith...

 of the observatory. It was long marked by a brass strip in the courtyard, now upgraded to stainless steel, and, since 16 December 1999, has been marked by a powerful green laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

 shining north across the London night sky.

This old astronomical prime meridian has been replaced by a more modern prime meridian. When Greenwich was an active observatory, geographical coordinates were referred to a local oblate spheroid called a datum, whose surface closely matched local mean sea level, called the geoid
Geoid
The geoid is that equipotential surface which would coincide exactly with the mean ocean surface of the Earth, if the oceans were in equilibrium, at rest , and extended through the continents . According to C.F...

. Several datums were in use around the world, all using different spheroids, because mean sea level undulates by as much as 100 metres worldwide. Modern geodetic reference systems, such as the World Geodetic System
World Geodetic System
The World Geodetic System is a standard for use in cartography, geodesy, and navigation. It comprises a standard coordinate frame for the Earth, a standard spheroidal reference surface for raw altitude data, and a gravitational equipotential surface that defines the nominal sea level.The latest...

 and the International Terrestrial Reference Frame, use a single Earth-centered oblate spheroid. The shift from several spheroids to one worldwide spheroid caused all geographical coordinates to shift by many metres, sometimes as much as several hundred metres. The Prime Meridian of these modern reference systems is 102.5 metres east of the Greenwich astronomical meridian represented by the stainless steel strip. Thus the strip is now 5.31 arcseconds West. The modern location of the Airy Transit is 51°28′40.1247"N 0°0′5.3101"W

Greenwich Mean Time

Greenwich Mean Time
Greenwich Mean Time
Greenwich Mean Time is a term originally referring to mean solar time at the Royal Observatory in Greenwich, London. It is arguably the same as Coordinated Universal Time and when this is viewed as a time zone the name Greenwich Mean Time is especially used by bodies connected with the United...

 (GMT) was at one time based on the time observations made at Greenwich (until 1954). Thereafter, GMT was calculated from observations made at other observatories which were still active. GMT is now often called Universal Time
Universal Time
Universal Time is a time scale based on the rotation of the Earth. It is a modern continuation of Greenwich Mean Time , i.e., the mean solar time on the Prime Meridian at Greenwich, and GMT is sometimes used loosely as a synonym for UTC...

, which is now calculated from observations of extra-galactic radio sources, and then converted into several forms, including UT0 (UT at the remote observatory), UT1 (UT corrected for polar motion
Polar motion
Polar motion of the earth is the movement of Earth's rotational axis across its surface. This is measured with respect to a reference frame in which the solid Earth is fixed...

), and UTC
Coordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...

 (UT in discrete SI seconds within 0.9 s of UT1). To help others synchronise their clocks to GMT, a time ball
Time ball
A time ball is a large painted wooden or metal ball that drops at a predetermined time, principally to enable sailors to check their marine chronometers from their boats offshore...

 was installed by Astronomer Royal John Pond
John Pond
John Pond FRS was a renowned English astronomer who became the sixth Astronomer Royal, serving from 1811 to 1835.- Biography :...

 in 1833. It still drops daily to mark the exact moment of 1 pm (13:00) year round (GMT during winter and BST
British Summer Time
Western European Summer Time is a summer daylight saving time scheme, 1 hour ahead of Coordinated Universal Time. It is used in the following places:* the Canary Islands* Portugal * Ireland...

 during summer).

Bomb attack of 1894

The Observatory underwent an attempted bombing in 1894. This was possibly the first 'international terrorist' incident in Britain. The bomb was detonated by a 26-year-old French anarchist named Martial Bourdin. It is not known why he chose the observatory, or whether the detonation was intended to occur elsewhere. The incident was used as inspiration by Joseph Conrad
Joseph Conrad
Joseph Conrad was a Polish-born English novelist.Conrad is regarded as one of the great novelists in English, although he did not speak the language fluently until he was in his twenties...

 in his novel The Secret Agent
The Secret Agent
The Secret Agent: A Simple Tale is a novel by Joseph Conrad published in 1907. The story is set in London in 1886 and deals largely with the life of Mr. Verloc and his job as a spy. The Secret Agent is also notable as it is one of Conrad's later political novels, which move away from his typical...

.

Observatory today

Today the buildings include a museum of astronomical and navigational tools, which is part of the National Maritime Museum
National Maritime Museum
The National Maritime Museum in Greenwich, England is the leading maritime museum of the United Kingdom and may be the largest museum of its kind in the world. The historic buildings forming part of the Maritime Greenwich World Heritage Site, it also incorporates the Royal Observatory, Greenwich,...

, notably including John Harrison
John Harrison
John Harrison was a self-educated English clockmaker. He invented the marine chronometer, a long-sought device in solving the problem of establishing the East-West position or longitude of a ship at sea, thus revolutionising and extending the possibility of safe long distance sea travel in the Age...

's prize-winning longitude marine chronometer
Marine chronometer
A marine chronometer is a clock that is precise and accurate enough to be used as a portable time standard; it can therefore be used to determine longitude by means of celestial navigation...

, H4, and its three predecessors, although all four are the property of the Ministry of Defence
Ministry of Defence (United Kingdom)
The Ministry of Defence is the United Kingdom government department responsible for implementation of government defence policy and is the headquarters of the British Armed Forces....

. Several additional horological artefacts are also displayed, documenting the history of precision timekeeping for navigational and astronomical purposes, including the mid 20th century Russian-made F.M. Fedchenko clock (the most accurate pendulum clock ever built in multiple copies). It is also home to the 28-inch Grubb
Howard Grubb
Sir Howard Grubb FRS was an optical designer from Dublin, Ireland. He was head of a family firm that made large optical telescopes, telescope drive controls, and other optical instruments...

 refracting telescope
Refracting telescope
A refracting or refractor telescope is a type of optical telescope that uses a lens as its objective to form an image . The refracting telescope design was originally used in spy glasses and astronomical telescopes but is also used for long focus camera lenses...

 of 1893, the largest of its kind in the UK. The Shepherd Clock
Shepherd gate clock
The Shepherd Gate Clock is the clock mounted on the wall outside the gate of the Royal Greenwich Observatory building in Greenwich, London. The clock, an early example of an electric clock, was a slave mechanism controlled by electric pulses transmitted by a master clock inside the main building...

 outside the observatory gate is an early example of an electric slave clock. In February 2005 construction work began on a £15 million redevelopment project to provide a new planetarium
Planetarium
A planetarium is a theatre built primarily for presenting educational and entertaining shows about astronomy and the night sky, or for training in celestial navigation...

 and additional display galleries and educational facilities. The 120 seat Peter Harrison Planetarium
Peter Harrison Planetarium
The Peter Harrison Planetarium is a 120-seat digital laser planetarium, situated in Greenwich Park, London and is part of the National Maritime Museum. It opened on May 25, 2007....

 officially opened on 25 May 2007.

Royal Observatory, Greenwich vs. Royal Greenwich Observatory

During much of the twentieth century, the Royal Greenwich Observatory was not at Greenwich. The last time that all departments were there was 1924: in that year electrification of the railways affected the readings of the Magnetic
Magnetism
Magnetism is a property of materials that respond at an atomic or subatomic level to an applied magnetic field. Ferromagnetism is the strongest and most familiar type of magnetism. It is responsible for the behavior of permanent magnets, which produce their own persistent magnetic fields, as well...

 and Meteorological
Meteorology
Meteorology is the interdisciplinary scientific study of the atmosphere. Studies in the field stretch back millennia, though significant progress in meteorology did not occur until the 18th century. The 19th century saw breakthroughs occur after observing networks developed across several countries...

 Department and forced its move to Abinger
Abinger
Abinger is a civil parish in the Mole Valley district of Surrey, England. It includes the villages of Abinger Hammer, Sutton Abinger, Abinger Common and part of Holmbury St Mary ....

. Indeed prior to this, the observatory had to insist that all the electric trams in the vicinity could not use an earth return for the traction current. In 1939, during World War II, many departments were evacuated, along with the rest of London, to the countryside (Abinger, Bradford
Bradford
Bradford lies at the heart of the City of Bradford, a metropolitan borough of West Yorkshire, in Northern England. It is situated in the foothills of the Pennines, west of Leeds, and northwest of Wakefield. Bradford became a municipal borough in 1847, and received its charter as a city in 1897...

, and Bath) and activities in Greenwich were reduced to the bare minimum.

After the War, in 1947, the decision was made to move to Herstmonceux Castle
Herstmonceux Castle
Herstmonceux Castle is a brick-built Tudor castle near Herstmonceux, East Sussex, United Kingdom. From 1957 to 1988 its grounds were the home of the Royal Greenwich Observatory...

 and 320 adjacent acres (1.3 km²), 70 km south-southeast of Greenwich near Hailsham
Hailsham
Hailsham is a civil parish and the largest of the five main towns in the Wealden district of East Sussex, England. Mentioned in the Domesday Book, the town of Hailsham has had a long history of industry and agriculture...

 in East Sussex, due to light pollution
Light pollution
Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.The International Dark-Sky Association defines light pollution as:...

 in London. Although the Astronomer Royal Harold Spencer Jones moved to the castle in 1948, the scientific staff could not move until the completion of new observatory buildings in 1957. Shortly thereafter, other far flung departments were reintegrated at Herstmonceux.

The Isaac Newton Telescope
Isaac Newton Telescope
The Isaac Newton Telescope or INT is a 2.54 m optical telescope run by the ING at Roque de los Muchachos Observatory on La Palma in the Canary Islands since 1984....

 was built at Herstmonceux in 1967, but was moved to Roque de los Muchachos Observatory
Roque de los Muchachos Observatory
Roque de los Muchachos Observatory is an astronomical observatory located in the municipality of Garafía on the island of La Palma in the Canary Islands...

 in Spain's Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...

 in 1979. In 1990 the RGO moved again, to Cambridge
Cambridge
The city of Cambridge is a university town and the administrative centre of the county of Cambridgeshire, England. It lies in East Anglia about north of London. Cambridge is at the heart of the high-technology centre known as Silicon Fen – a play on Silicon Valley and the fens surrounding the...

. Following a decision of the Particle Physics and Astronomy Research Council
Particle Physics and Astronomy Research Council
The Particle Physics and Astronomy Research Council was one of a number of Research Councils in the United Kingdom. It directed, coordinated and funded research in particle physics and astronomy for the people of the UK...

, it closed in 1998. Her Majesty's Nautical Almanac Office was transferred to the Rutherford Appleton Laboratory
Rutherford Appleton Laboratory
The Rutherford Appleton Laboratory is one of the national scientific research laboratories in the UK operated by the Science and Technology Facilities Council . It is located on the Harwell Science and Innovation Campus at Chilton near Didcot in Oxfordshire, United Kingdom...

 after the closure. Other work went to the UK Astronomy Technology Centre
UK Astronomy Technology Centre
The UK Astronomy Technology Centre is based at the Royal Observatory in Edinburgh, Scotland, and is part of the Science and Technology Facilities Council....

 in Edinburgh. The castle grounds are now the home of the International Study Centre of Queen's University, Kingston, Canada and The Observatory Science Centre which is operated by an educational charity Science Projects
Science Projects Limited
Science Projects Limited is a company with charitable status founded by Stephen Pizzey 1986 to aid public understanding of science through interactive exhibits. It operates The Observatory Science Centre in the south east of England at the former home of the Royal Greenwich Observatory which moved...

.

Chronology

  • 1675 Royal Observatory, Greenwich founded.
  • 1714 Longitude Act
    Longitude Act 1714
    The Longitude Act was an Act of Parliament of the United Kingdom passed in July 1714 during the reign of Queen Anne. It established the Board of Longitude and offered a monetary reward for anyone who could find a simple and practical method for the precise determination of a ship's...

     establishes the Board of Longitude
    Board of Longitude
    The Board of Longitude was the popular name for the Commissioners for the Discovery of the Longitude at Sea. It was a British Government body formed in 1714 to administer a scheme of prizes intended to encourage innovators to solve the problem of finding longitude at sea.-Origins:Navigators and...

     and the Longitude prize
    Longitude prize
    The Longitude Prize was a reward offered by the British government for a simple and practical method for the precise determination of a ship's longitude...

  • 1924 Hourly time signals (Greenwich Time Signal
    Greenwich Time Signal
    The Greenwich Time Signal , popularly known as the pips, is a series of six short tones broadcast at one-second intervals by many BBC Radio stations to mark the precise start of each hour...

    ) from the Royal Observatory, Greenwich were first broadcast on 5 February.
  • 1948 Astronomer Royal moves to Herstmonceux.
  • 1957 Royal Observatory completes its move to Herstmonceux, becoming the Royal Greenwich Observatory (RGO). The Greenwich site becomes the Old Royal Observatory.
  • 1990 RGO moves to Cambridge.
  • 1998 RGO closes. Greenwich site becomes the Royal Observatory, Greenwich again, and is part of the National Maritime Museum
    National Maritime Museum
    The National Maritime Museum in Greenwich, England is the leading maritime museum of the United Kingdom and may be the largest museum of its kind in the world. The historic buildings forming part of the Maritime Greenwich World Heritage Site, it also incorporates the Royal Observatory, Greenwich,...

    .

Further reading

  • Greenwich Observatory: ... the Royal Observatory at Greenwich and Herstmonceux, 1675–1975. London: Taylor & Francis, 1975 3v. (Vol. 1. Origins and early history (1675–1835), by Eric G. Forbes. ISBN 0-85066-093-9; Vol. 2. Recent history (1836–1975), by A.J. Meadows. ISBN 0-85066-094-7; Vol. 3. The buildings and instruments by Derek Howse. ISBN 0-85066-095-5).
  • Greenwich Time and the Longitude. London: Philip Wilson, 1997, by Derek Howse. ISBN 0-85667-468-0.

External links

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