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A 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.
Longitude by chronometer is a method, in navigation, of determining longitude using a marine chronometer, which was developed by John Harrison during the first half of the eighteenth century. It is an astronomical method of calculating the longitude at which a position line, drawn from a sight by sextant of any celestial body, crosses the ...
Marine chronometer used to determine time at the prime meridian with great precision which is necessary when reducing sights in celestial navigation. Nocturnal used to determine apparent local time by viewing the Polaris and its surrounding stars. Ring dial or astronomical ring used to measure the height of a celestial body above the horizon ...
A chronometer (Ancient Greek: χρονόμετρον, khronómetron, "time measurer") is an extraordinarily accurate mechanical timepiece, with an original focus on the needs of maritime navigation. In Switzerland , timepieces certified by the Contrôle Officiel Suisse des Chronomètres ( COSC ) may be marked as Certified Chronometer or ...
The Model 21 Hamilton Marine Chronometer for large vessels was built first and had a chain-drive fusee, the second hand advanced in 1 ⁄ 2-second increments over a 60-second-marked sub-dial, and was kept in a traditional gimbaled double box for the express purpose of keeping the clock in a "dial up" position to minimize ship-movement-induced ...
Thomas moved to Liverpool to continue working as a watchmaker in 1843, and thence to London in 1854, to buy a one-way ticket to the USA, in search of new and better prospects. Seeing a chronometer in the window of John Fletcher (chronometer makers), he changed his mind about the USA, asking for work and being hired on the spot. [3]
A boxed chronometer is mounted on gimbals attached to its box. A pocket chronometer is in the style of a pocketwatch. "Winding" refers to the number of days that a chronometer kept going before needing rewinding. However, they were all wound at precisely the same time every day, except for the eight-day chronometers which were wound weekly. [22]
John Harrison (3 April [O.S. 24 March] 1693 – 24 March 1776) was an English carpenter and clockmaker who invented the marine chronometer, a long-sought-after device for solving the problem of how to calculate longitude while at sea. Harrison's solution revolutionized navigation and greatly increased the safety of long-distance sea travel.