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Time ball

Time ball

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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 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...

s from their boats offshore. Accurate timekeeping is one way of enabling mariners to determine their 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 ....

 at sea.


Time ball stations set their clocks according to transit observations of the positions of the sun and stars. Originally they either had to be stationed at the observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...

 itself, or had to keep a very accurate clock at the station which was set manually to observatory time. Following the introduction of the electric telegraph around 1850, time balls could be located at a distance from their source of Meantime
Meantime is the second album and major-label debut by Helmet, released in 1992 on Interscope Records. Meantime has continued to sell consistently well in the years since its release, and in 1994 was certified gold by the Recording Industry Association of America.Helmet released one single from...

 and operated remotely.

The first time ball was erected at Portsmouth
Portsmouth is the second largest city in the ceremonial county of Hampshire on the south coast of England. Portsmouth is notable for being the United Kingdom's only island city; it is located mainly on Portsea Island...

, England in 1829 by its inventor Robert Wauchope, a Captain in the Royal Navy
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

. Others followed in the major ports of the United Kingdom (including Liverpool
Liverpool is a city and metropolitan borough of Merseyside, England, along the eastern side of the Mersey Estuary. It was founded as a borough in 1207 and was granted city status in 1880...

) and around the maritime world. One was installed in 1833 at the Greenwich Observatory
Royal Observatory, Greenwich
The Royal Observatory, Greenwich , in London, England played a major role in the history of astronomy and navigation, and is best known as the location of the prime meridian...

 by 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....

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

, and the time ball has dropped at 1 p.m. every day since then. Wauchope submitted his scheme to American and French ambassadors when they visited England. The US Naval Observatory was established in Washington D.C. and the first American time ball went into service in 1845.

Time balls are usually dropped at 1 p.m. (although in the USA they were dropped at noon). They were raised half way about 5 minutes earlier to alert the ships, then with 2–3 minutes to go they were raised the whole way. The time was recorded when the ball began descending, not when it reached the bottom.

With the commencement of radio time signals
Time signal
A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.-Audible and visible time signals:...

 (in Britain from 1924), time-balls gradually became obsolete and many were demolished in the 1920s.

Surviving time balls

Today there are over sixty time balls standing, though many of these are no longer operational. The existing stations include those at:
  • Deal, Kent
  • Fremantle, Western Australia
    Fremantle, Western Australia
    Fremantle is a city in Western Australia, located at the mouth of the Swan River. Fremantle Harbour serves as the port of Perth, the state capital. Fremantle was the first area settled by the Swan River colonists in 1829...

  • Gdańsk
    Gdańsk is a Polish city on the Baltic coast, at the centre of the country's fourth-largest metropolitan area.The city lies on the southern edge of Gdańsk Bay , in a conurbation with the city of Gdynia, spa town of Sopot, and suburban communities, which together form a metropolitan area called the...

    , Poland (The time ball was installed in 1876, moved to the Danzig (now Gdańsk) lighthouse in 1894, and removed in 1929. In 2008 it was reconstructed from original plans and continues to operate today)
  • Greenwich Observatory
  • Clock Tower, Brighton
    Clock Tower, Brighton
    The Clock Tower is a free-standing clock tower in the centre of Brighton, part of the English city of Brighton and Hove. Built in 1888 in commemoration of Queen Victoria's Golden Jubilee, the distinctive structure included innovative structural features and became a landmark in the popular and...

    , East Sussex (originally operated hourly, but was later stopped as it was too noisy)
  • Nelson's Monument on Calton Hill, Edinburgh
    Edinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...

  • Point Gellibrand, Victoria
  • Sydney Observatory
    Sydney Observatory
    Sydney Observatory is located on a hill now known as 'Observatory Hill' in an area in the centre of Sydney. The site evolved from a fort built on 'Windmill Hill' in the early 19th century to an astronomical observatory during the nineteenth century...

    , Australia
  • Victoria & Alfred Waterfront
    Victoria & Alfred Waterfront
    The Victoria & Alfred Waterfront in the historic heart of Cape Town's working harbour is South Africa's most-visited destination, having the highest rate of foreign tourists of any attraction in the country...

    , Cape Town
    Cape Town
    Cape Town is the second-most populous city in South Africa, and the provincial capital and primate city of the Western Cape. As the seat of the National Parliament, it is also the legislative capital of the country. It forms part of the City of Cape Town metropolitan municipality...

  • United States Naval Observatory
    United States Naval Observatory
    The United States Naval Observatory is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation, and Timing for the U.S. Navy and the U.S. Department of Defense...

  • Titanic memorial park
    Titanic Memorial (New York City)
    The Titanic Memorial is a lighthouse built, due in part to the instigation of Margaret Brown, to remember the people who died on the RMS Titanic on April 15, 1912.- History :The lighthouse was originally erected by public subscription in 1913...

    , South Street Seaport
    South Street Seaport
    The South Street Seaport is a historic area in the New York City borough of Manhattan, located where Fulton Street meets the East River, and adjacent to the Financial District. The Seaport is a designated historic district, distinct from the neighboring Financial District...

    , New York City
    New York City
    New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...

    , NY
    New York
    New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...

  • Citadelle of Quebec
    Citadelle of Quebec
    The Citadelle — the French name is used both in English and French — is a military installation and official residence located atop Cap Diamant, adjoining the Plains of Abraham in Quebec City, Quebec, Canada...

    , Quebec City
    Quebec City
    Quebec , also Québec, Quebec City or Québec City is the capital of the Canadian province of Quebec and is located within the Capitale-Nationale region. It is the second most populous city in Quebec after Montreal, which is about to the southwest...

  • Semaphore
    Semaphore, South Australia
    Semaphore is a north-western seaside suburb of Adelaide of the LeFevre Peninsula 14km from the CBD, in the state of South Australia, Australia and falls under the City of Port Adelaide Enfield. It is adjacent to Semaphore South, Glanville, Exeter and Largs Bay. The postcode for Semaphore is 5019...

    , South Australia

The Lyttelton Timeball Station
Lyttelton Timeball Station
The Lyttelton Timeball Station was a heritage-registered timeball station and prominent local landmark in Lyttelton, New Zealand. The station was significantly damaged by a series of earthquakes and aftershocks in 2010 and 2011, and finally collapsed on the 13 June 2011 after a magnitude 6.3...

 in Lyttelton, New Zealand
Lyttelton, New Zealand
Lyttelton is a port town on the north shore of Lyttelton Harbour close to Banks Peninsula, a suburb of Christchurch on the eastern coast of the South Island of New Zealand....

 was operational until it received partial damage in the 2010 Canterbury earthquake
2010 Canterbury earthquake
The 2010 Canterbury earthquake was a 7.1 magnitude earthquake, which struck the South Island of New Zealand at 4:35 am on local time ....

. Further severe damage occurred in the February 2011 Christchurch earthquake and a decision was made in March 2011 to dismantle the building due to the danger it posed to the public. The tower collapsed during the major aftershock
June 2011 Christchurch earthquake
The June 2011 Christchurch earthquake was a shallow magnitude 6.3 ML earthquake that occurred on 13 June 2011 at 14:20 NZST . It was centred at a depth of 6.0 km , about 13 km from Christchurch, which had previously been devastated by the February 2011 magnitude 6.3 ML earthquake...

 which hit the Lyttelton area on 13 June 2011.

Times Square New Year's Eve ball

A modern variant on the time ball is the ball drop
Times Square Ball
The Times Square Ball is a time ball dropped each year during the New Year’s Eve celebration in Times Square, Manhattan, New York City. The ball is made by Waterford Crystal and electric lights is raised to the top of a pole on the One Times Square building at 6:00 pm and then lowered to mark the...

 on New Year's Eve
New Year's Eve
New Year's Eve is observed annually on December 31, the final day of any given year in the Gregorian calendar. In modern societies, New Year's Eve is often celebrated at social gatherings, during which participants dance, eat, consume alcoholic beverages, and watch or light fireworks to mark the...

, notably in Times Square
Times Square
Times Square is a major commercial intersection in the borough of Manhattan in New York City, at the junction of Broadway and Seventh Avenue and stretching from West 42nd to West 47th Streets...

, New York City
New York City
New York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...

. Unlike a standard time ball, where the drop starts at exactly noon or 1 p.m., the Times Square drop starts at 11:59:00pm on December 31 and completes a minute later at midnight on January 1. When a leap second
Leap second
A leap second is a positive or negative one-second adjustment to the Coordinated Universal Time time scale that keeps it close to mean solar time. UTC, which is used as the basis for official time-of-day radio broadcasts for civil time, is maintained using extremely precise atomic clocks...

 was observed at the end of 1987, the drops lasted 61 seconds with the countdown
A countdown is a sequence of counting backward to indicate the seconds, days, or other time units remaining before an event occurs or a deadline expires. Typical events for which a countdown is used include the launch of a rocket or spacecraft, the detonation of a bomb, the start of a race, and the...

 being ... 5, 4, 3, 2, 1, Leap Second, Zero. (At the time, the leap second was added at local time; since 1988, leap seconds have been appended worldwide at midnight 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...


See also

  • Blackhead Point
    Blackhead Point
    Blackhead Point , also known as Tai Pau Mai indigenously, Tsim Sha Tsui Point or Signal Hill , was a cape before any reclamation in Tsim Sha Tsui, Kowloon, Hong Kong...

    , in Hong Kong, where a time ball was operated from 1908 to 1933
  • History of longitude
    History of longitude
    The history of longitude is a record of the effort, by navigators and scientists over several centuries, to discover a means of determining longitude....

  • Shepherd gate 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...

  • Time signal
    Time signal
    A time signal is a visible, audible, mechanical, or electronic signal used as a reference to determine the time of day.-Audible and visible time signals:...

  • Weather ball