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 International latitude observatory of Ukiah, California, 1908 | |
| Alternative names | International Polar Motion Service |
|---|---|
| Location | United States |
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TheInternational Latitude Service[1] was created by theInternational Geodetic Association in 1899 to study variations inlatitude caused bypolar motion,precession, or"wobble" of the Earth's axis.
In 1891, at the meeting of the Permanent Commission of the International Geodetic Association in Florence,Wilhelm Foerster referred to the discovery bySeth Carlo Chandler of thepolar motion predicted byLeonhard Euler in 1765 and his impact on the determinationlatitudes. He proposed that theInternational Geodetic Association implement a systematic study of this important phenomenon. In 1895, the creation of the International Latitude Service was decided by the International Geodesic Association. Its central office was based in Potsdam and headed byFriedrich Robert Helmert. Regular observations began in 1899. After 1916, the operations of the International Latitudes Service continued under the aegis of the Reduced Geodetic Association among Neutral States presided by Raoul Gautier director ofGeneva Observatory.[2][3][4][5]
The originalInternational Latitude Observatories were a system of sixobservatories located near theparallel of 39° 08' north latitude. The alignment of all six stations along the parallel helped the observatories to perform uniform data analysis. The original six observatories were located in:
Twelve groups of stars were studied in the program, each group containing six pairs of stars. Each night, each station observed two of the star groups along a preset schedule and later compared the data against the measurements taken by the sister stations.Economic difficulties and war caused the closings of some of the original stations, though a newer station was created in Uzbekistan afterWorld War I. The data collected by the observatories over the years still has use to scientists, and has been applied to studies of polar motion, the physical properties of the Earth, climatology andsatellite tracking andnavigation.
The final six observatories were located, in order of Longitude (E to W), in:
The ILS was renamedInternational Polar Motion Service (IPMS) in 1962. It was replaced when theInternational Earth Rotation Service (IERS) was established in 1987.
{{cite book}}:ISBN / Date incompatibility (help)| International | |
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39°08′12.51″N77°11′55.85″W / 39.1368083°N 77.1988472°W /39.1368083; -77.1988472 (Gaithersburg Latitude Observatory)39°08′20.45″N84°25′24″W / 39.1390139°N 84.42333°W /39.1390139; -84.42333 (Cincinnati Latitude Observatory)39°08′14.26″N123°12′42.54″W / 39.1372944°N 123.2118167°W /39.1372944; -123.2118167 (Ukiah Latitude Observatory)39°08′6″N141°07′54″E / 39.13500°N 141.13167°E /39.13500; 141.13167 (Mizusawa Latitude Observatory)39°08′0″N66°52′54″E / 39.13333°N 66.88167°E /39.13333; 66.88167 (Kitab Latitude Observatory)39°08′13.76″N8°18′41.90″E / 39.1371556°N 8.3116389°E /39.1371556; 8.3116389 (Carloforte Latitude Observatory)
