International Polar Motion Service
The International Polar Motion Service (IPMS) is the successor to the International Broad Service . It served from the 1970s for the precise monitoring of the earth's rotation and its polar movement and was merged with the time services to form the International Service for Earth Rotation and Reference Systems (IERS) in the 1980s .
history
The effect of the pole movement or "pole fluctuation" - a small, periodic displacement of the north and south poles within the earth's body of around ten meters - was already suspected in the mid-19th century and in 1885 by the German astronomer Friedrich Küstner (1856–1936) through precise measurements the pole height ( geographical latitude ) in Bonn.
The 1899 by Carl Theodor Albrecht , Wilhelm Foerster and Friedrich Robert Helmert in Berlin International width service founded should this effect through coordinated measurement campaigns on several observatories more accurately detect and analyze because of longer series of measurements already at that time the small width changes to about ± 0.05 " exactly if they took place on opposite continents.
For the first few decades, the broad service relied on precise measurements of the polar height at five globally distributed fundamental stations in Europe, Asia, the USA and Japan, all of which were on the same parallel of 39 ° 08 ′. This made it possible for all five observatories to observe the same stars and to eliminate small systematic sources of error in the star locations and the season . The measurements were initially carried out exclusively with star passages according to the Horrebow-Talcott method and using passage instruments as well as stationary zenith telescopes .
This visual observation technique was later supplemented by semi-automatic astrolabe measurements and, from the 1970s, by methods of satellite geodesy . The headquarters of the organization also moved to Washington and Japan.
When in the 1980s the accuracy was increased to the range of a few centimeters and supplemented by astronomical radio interferometry ( VLBI ), it was decided to combine all permanent measurement campaigns in the International Earth Rotation Service (IERS). Since then he has also been responsible for the reference system of the time and partly the celestial coordinates and currently has his central office in Frankfurt / Main.
See also
- Fundamental system (astronomy) , geodetic reference system 1980
- Earth rotation parameters , inertial system
- Atomic time , world time , Sterneck method
- Geodynamics
Literature and web links
- Karl Ramsayer : Geodetic Astronomy . JEK Volume 2A, Wittwer, Stuttgart 1969
- History of astronomy
- J. Höpfner: The International Latitude Service – A Historical Review, From The Beginning To Its Foundation In 1899 And The Period Until 1922 . In: Surveys in geophysics . tape 21 , no. 5 , 2000, pp. 521-566 , doi : 10.1023 / A: 1006701327419 .