Title: PRECISE ASTRONOMICAL FIXES
Author(s): Giles G. Healey
Published in: NAVIGATION, Journal of the Institute of Navigation, Volume 3, Number 4
Pages: 110 - 117
Cite this article: Healey, Giles G., "PRECISE ASTRONOMICAL FIXES", NAVIGATION, Journal of The Institute of Navigation, Vol. 3, No. 4, 1952-1953, pp. 110-117.
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Abstract: About three hundred astronomical observatories throughout the world give us their position to tenths of a second in Latitude and hundredths of a second in Longitude. These are their astronomical positions but they are often quite ignorant of their exact geographical location. The reason for this is that the earth is irregular in shape and only by elaborate surveys, computations, and a reduction to a preselected earth shape can the coordinates of a station be secured. The earth is assumed to have different shapes by different countries and the reference ellipsoid can be either the Everest, the Bessel, one of the three Clarke’s, the Helmert, the Hayford or the Madrid 1924 (International) figure. The tie-in reference point for Canada, Mexico and the United States is at Meades Ranch, Kansas with a Latitude of 39”13’ 26.686” and a Longitude of 98”32’ 30.506”.