SIGHT REDUCTION USING THE PORTABLE SEXTANT COMPUTER SYSTEM

Sight reduction procedures in marine navigation have been traditional for nearly a century and a half, just as the marine sextant, itself, has been essentially the same design for 250 years. The reduction of each sextant sight to true azimuth and altitude intercept requires the use of standard forms, The Nautical Almanac, and several volumes of sight reduction tables. The procedure is tedious and time consuming, and errors in data selection and arithmetic are common. A low-cost, specialized, small portable computer that operates with the sextant can be developed to relieve the navigator of his calculation tedium and blunders and improve his navigation accuracy. The design of such a small computer is feasible today. The logic and a functional computer program have been developed that combines the necessary data and spherical trigonometric equations to reduce the altitude measurements of the stars to data ready for plotting by the navigator. This paper will discuss the new digital readout day/night marine sextant which is part of the concept of the portable sextant-computer system, the development of the program for the computer, and its application to solve navigation problems. Furthermore, use of the portable computer will be shown to be applicable to all fields of navigation, although the current development centers around marine navigation.

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    Institute of Navigation

    815 14th Street, NW
    Washington, DC  USA  20005
  • Authors:
    • Feldman, S
    • Seidelmann, P K
    • Stephenson, E D
    • Ketts, H C
  • Publication Date: 1972-12

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Filing Info

  • Accession Number: 00044410
  • Record Type: Publication
  • Source Agency: Institute of Navigation
  • Files: TRIS
  • Created Date: May 11 1973 12:00AM