DSKR SEXTANT MADE IN DDR (MRA 113)

Item Code: MRA 113

Description

A 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. 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. The principle of the instrument was first implemented around 1730 by John Hadley (1682–1744) and Thomas Godfrey (1704–1749), but it was also found later in the unpublished writings of Isaac Newton (1643–1727). In 1922, it was modified for aeronautical navigation by Portuguese navigator and Naval Officer Gago Coutinho.
Sextant allows celestial objects to be measured relative to the horizon, rather than relative to the instrument. This allows excellent precision. However, unlike the backstaff, the sextant allows direct observations of stars. This permits the use of the sextant at night when a backstaff is difficult to use. For solar observations, filters allow direct observation of the sun.

There are no reviews yet.

Only logged in customers who have purchased this product may leave a review.

  • C.PLATH HAMBURG HELMET BINNACLE COMPASS WITH LAMP MOUNT (MRA 009)

    $1,150.00
  • OPTIM US SWEDEN NO 510 BURNER (MRA 017)

    $250.00
  • VINTAGE METALIC SPOT LIGHT (MRA 025)

    $180.00
  • ELECTRIC ENGINE TELEGRAPH BY NUNOTANIl KEIKI SEISAKUSHO (MRA 018)

    $950.00
  • ON BRITISH MADE BAROMETER (MRA 014)

    $370.00
  • ROOF HUNG MARINE LIGHT (BLUE) (MRA 011)

    $1.00
  • NIPPON SENTO VINTAGE MARINE LAMP (AQUATIC BLUE) (MRA 020)

    $380.00
  • LILLEY & GILLIE MARINE BAROMETER (MRA 015)

    $370.00
  • EIWA SEIKO ENGINE ORDER TELEGRAPH (MRA 003)

    $1,500.00
  • ViINTAGE ANEROID BAROMETER BY TAKAHASHI (MRA 032)

    $370.00