Longitude scientific biography

  • Who figured out longitude
  • How do you determine longitude
  • Longitude book

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    Longitude

    Geographic coordinate that specifies the east-west position of a point on the Earth's surface

    For other uses, see Longitude (disambiguation).

    Longitude (, AU and UK also)[1][2] is a geographic coordinate that specifies the east-west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek letterlambda (λ). Meridians are imaginary semicircular lines running from pole to pole that connect points with the same longitude. The prime meridian defines 0° longitude; by convention the International Reference Meridian for the Earth passes near the Royal Observatory in Greenwich, south-east London on the island of Great Britain. 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 measurement. Scientifically precise local time varies with

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    Longitude, as a geographical coordinate, identifies east-west position on Earth, with lines of longitude, or meridians, running from pole to pole. Because of the Earth’s rotation, the difference in longitude between two locations is equivalent to the difference in their local times: one degree of longitude equals a four-minute time difference, and 15 degrees is equal to one hour (making 360 degrees, or 24 hours, in total). There is no naturally occurring zero point, or prime meridian, and so it is for historical and contingent reasons that we have come to measure longitude from a meridian that runs through Greenwich, near London in the United Kingdom. Longitude was far more difficult than latitude (north-south position) to measure by astronomical observation. Latitude is defined in relation to the equator and could be calculated by observing the maximum altitudes of the Sun or other stars using instruments such as astrolabes, cross-staffs and back-staffs. Longitude, in contrast, ca

  • longitude scientific biography

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    Longitude (book)

    1995 popular science book

    Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time is a 1995 best-selling book bygd Dava Sobel about John Harrison, an 18th-century clockmaker who created the first clock (chronometer) sufficiently accurate to be used to determine longitude at sea—an important development in navigation. The book was made into a television series entitled Longitude.[1] In 1998, The Illustrated Longitude was published, supplementing the earlier text with 180 images of characters, events, instruments, maps and publications.

    Problem of longitude

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    Determining longitude on land was fairly easy compared to the task at sea. A stable surface to work from, known coordinates to refer to, a sheltered environment for the unstable chronometers of the day, and the ability to repeat determinations over time made for great accuracy.

    For calculating longitude at sea however, early ocean navigators