Navigation

Cosma / Communication / Knowledge / Realm / Geography / Navigation

An exception to stellar rotation,
The Pole Star has one fixed location.
This celestial clue
To the North points you to
A direction for true navigation. — DenmarK, Celestial navigation

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Introduction¹

Dictionary

navigation : the method of getting ships, aircraft, or spacecraft from place to place, especially : the method of determining position, course, and distance traveled — Webster

Free Dictionary, Wiktionary, OneLook

Thesaurus

Roget’s II (Thesaurus.com), Merriam-Webster Thesaurus, Visuwords

Glossary

Navigation Glossary (International Association of Institutes of Navigation)
Navigation Acronyms, Abbreviations and Definitions (Royal Institute of Navigation)

Encyclopedia

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. All navigational techniques involve locating the navigator’s position compared to known locations or patterns. — Wikipedia

Navigation (Encyclopædia Britannica)

Search

Geodesy & Navigation (WolframAlpha)

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Preservation

History

Celestial navigation also known as astronavigation, is the ancient and continuing modern practice of position fixing using stars and other celestial bodies that enables a navigator to accurately determine their actual current physical position in space (or on the surface of the earth) without having to rely solely on estimated positional calculations, commonly known as dead reckoning. — Wikipedia

Celestial Navigation (Navigation Museum, The Institute of Navigation)
Celestial Navigation (Encyclopædia Britannica)

Sunstone is a type of mineral attested in 13th–14th century written sources in Iceland, one of which describes its use to locate the sun in an overcast sky. Sunstones are also mentioned in the inventories of several churches and one monastery in 14th–15th century Iceland and Germany. — Wikipedia

Vikings Navigated With Translucent Crystals? (Lucas Laursen, National Geographic)

Compass rose, sometimes called a wind rose, rose of the winds or compass star, is a figure on a compass, map, nautical chart, or monument used to display the orientation of the cardinal directions (north, east, south, and west) and their intermediate points. It is also the term for the graduated markings found on the traditional magnetic compass. — Wikipedia

The Art and Science of the Compass Rose (Eliane Dotson, Old World Auctions)
Compass rose (Encyclopædia Britannica)

Compass is a device that shows the cardinal directions used for navigation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with magnetic north. — Wikipedia

Compass 12th century (Smithsonian National Museum of American History)
Compass (National Geographic Society)
Compass (Encyclopædia Britannica)

Longitude is a geographic coordinate that specifies the east–west position of a point on the Earth’s surface, or the surface of a celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letter lambda (λ). Meridians (lines running from pole to pole) connect points with the same longitude. The prime meridian, which passes near the Royal Observatory, Greenwich, England, is defined as 0° longitude by convention. Positive longitudes are east of the prime meridian, and negative ones are west. Because of the Earth’s rotation, there is a close connection between longitude and time. Local time (for example from the position of the Sun) varies with longitude: a difference of 15° longitude corresponds to a one-hour difference in local time. Comparing local time to an absolute measure of time allows longitude to be determined. Depending on the era, the absolute time might be obtained from a celestial event visible from both locations, such as a lunar eclipse, or from a time signal transmitted by telegraph or radio. The principle is straightforward, but in practice finding a reliable method of determining longitude took centuries and required the effort of some of the greatest scientific minds. — Wikipedia

Lost at Sea: The Search for Longitude (NOVA, WGBH/PBS)
Secrets of Ancient Navigation (Lost at Sea: The Search for Longitude, NOVA, WGBH/PBS)
Lost at Sea: The Search for Longitude: Full Transcript (NOVA, WGBH/PBS)
Lost at Sea: The Search for Longitude: Full Video (NOVA, PBS @ Internet Archive)

Longitude at Sea (The Galileo Project)
Galileo’s Instruments of Discovery (Smithsonian Magazine)

Marine chronometer is a precision timepiece that is carried on a ship and employed in the determination of the ship’s position by celestial navigation. It is used to determine longitude by comparing Greenwich Mean Time (GMT) and the time at the current location found from observations of celestial bodies. When first developed in the 18th century, it was a major technical achievement, as accurate knowledge of the time over a long sea voyage is necessary for navigation, lacking electronic or communications aids. The first true chronometer was the life work of one man, John Harrison, spanning 31 years of persistent experimentation and testing that revolutionized naval (and later aerial) navigation. — Wikipedia

Longitude found: the story of Harrison’s clocks (National Maritime Museum, Royal Museums Greenwich)
Chronometer (Smithsonian National Museum of American History)

Chronometer (Encyclopædia Britannica)
John Harrison (Encyclopædia Britannica)

Board of Longitude (Wikipedia)

Editioning an archive – the Board of Longitude Project (Cambridge University Library)

Sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle, the altitude, is known as sighting or shooting the object, or taking a sight. The angle, and the time when it was measured, can be used to calculate a position line on a nautical or aeronautical chart—for example, sighting the Sun at noon or Polaris at night (in the Northern Hemisphere) to estimate latitude (with sight reduction). Sighting the height of a landmark can give a measure of distance off and, held horizontally, a sextant can measure angles between objects for a position on a chart. A sextant can also be used to measure the lunar distance between the moon and another celestial object (such as a star or planet) in order to determine Greenwich Mean Time and hence longitude. — Wikipedia

Prime meridian is the meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great circle. This great circle divides a spheroid into two hemispheres. If one uses directions of East and West from a defined prime meridian, then they can be called the Eastern Hemisphere and the Western Hemisphere. For Earth’s prime meridian, various conventions have been used or advocated in different regions. The Earth’s current international standard prime meridian is the IERS Reference Meridian. It is derived, but differs, from the Greenwich Meridian, the previous international standard. — Wikipedia