HM Nautical Almanac Office

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Nautical Almanac Office
Office overview
Jurisdiction Government of the United Kingdom
HeadquartersAdmiralty Building
Parent Office United Kingdom Hydrographic Office

Her Majesty's Nautical Almanac Office (HMNAO), now part of the United Kingdom Hydrographic Office, was established in 1832 on the site of the Royal Observatory, Greenwich (ROG), where The Nautical Almanac had been published since 1767. HMNAO produces astronomical data for a wide range of users, such as astronomers, mariners, aviators, surveyors, the military, Police, lawyers, religious groups, architects, schools, diary and calendar manufacturers, photographers and film crews.

United Kingdom Hydrographic Office

The United Kingdom Hydrographic Office (UKHO) is the UK's agency for providing hydrographic and marine geospatial data to mariners and maritime organisations across the world. The UKHO is a trading fund of the Ministry of Defence (MOD) and is located in Taunton, Somerset with a workforce of approximately 900 staff.

The Nautical Almanac has been the familiar name for a series of official British almanacs published under various titles since the first issue of The Nautical Almanac and Astronomical Ephemeris, for 1767: this was the first nautical almanac to contain data dedicated to the convenient determination of longitude at sea. It was originally published from the Royal Greenwich Observatory in England. A detailed account of how the publication was produced in its earliest years has been published by the National Maritime Museum.


In 1937, it became part of ROG and moved with it, when it moved away from Greenwich (and was renamed the Royal Greenwich Observatory) first to Herstmonceux Castle, near Hailsham in East Sussex in 1948, then to Cambridge in 1990. When the RGO closed in 1998 HMNAO was transferred to the Rutherford Appleton Laboratory, near Abingdon in Oxfordshire. In December 2006, HMNAO was transferred to the United Kingdom Hydrographic Office, which is based in Taunton in Somerset.

Herstmonceux Castle castle near Herstmonceux, East Sussex, England; formerly a manor

Herstmonceux Castle is a brick-built castle, dating from the 15th century, near Herstmonceux, East Sussex, England. It is one of the oldest significant brick buildings still standing in England. The castle was renowned for being one of the first buildings to use that material in England, and was built using bricks taken from the local clay, by builders from Flanders. It dates from 1441. Construction began under the then-owner, Sir Roger Fiennes and then, from his death in 1449, by his son, Lord Dacre.

Hailsham town

Hailsham is a civil parish and the largest of the five towns in the Wealden district of East Sussex, England. It is mentioned in the Domesday Book, where it is called Hamelesham. The town of Hailsham has a history of industry and agriculture.

East Sussex County of England

East Sussex is a county in South East England. It is bordered by the counties of Kent to the north and east, Surrey to the north west and West Sussex to the west, and to the south by the English Channel.

Leaders of HMNAO

Superintendents of the Nautical Almanac

Thomas Young (scientist) English polymath

Thomas Young FRS was a British polymath and physician. Young made notable scientific contributions to the fields of vision, light, solid mechanics, energy, physiology, language, musical harmony, and Egyptology. He "made a number of original and insightful innovations" in the decipherment of Egyptian hieroglyphs before Jean-François Champollion eventually expanded on his work. He was mentioned by, among others, William Herschel, Hermann von Helmholtz, James Clerk Maxwell, and Albert Einstein. Young has been described as "The Last Man Who Knew Everything".

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Polymath person whose expertise spans a significant number of different subject areas

A polymath is a person whose expertise spans a significant number of subject areas, known to draw on complex bodies of knowledge to solve specific problems.

Heads of HM Nautical Almanac Office


United States Naval Observatory scientific agency in the United States

The United States Naval Observatory (USNO) is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation and Timing (PNT) for the United States Navy and the United States Department of Defense. Located in Northwest Washington, D.C. at the Northwestern end of Embassy Row, it is one of the pre-1900 astronomical observatories located in an urban area; at the time of its construction, it was far from the light pollution thrown off by the (then-smaller) city center. Former USNO director Gernot M. R. Winkler initiated the "Master Clock" service that the USNO still operates, and which provides precise time to the GPS satellite constellation run by the United States Air Force. The USNO performs radio VLBI-based positions of quasars with numerous global collaborators, in order to produce Earth Orientation parameters.

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Nautical almanac publication describing the positions of selected celestial bodies for help in navigation

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The Astronomical Almanac is an almanac published by the United States Naval Observatory (USNO) and Her Majesty's Nautical Almanac Office (HMNAO); it also includes data supplied by many scientists from around the world. It is considered a worldwide resource for fundamental astronomical data, often being the first publication to incorporate new International Astronomical Union resolutions. The almanac largely contains solar system ephemeris and catalogs of selected stellar and extragalactic objects. The material appears in sections, each section addressing a specific astronomical category. The book also includes references to the material, explanations, and examples. It is available one year in advance of its date.

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