(Earth Rotation Data)
(Celestial Reference System)
Polar motion for the last years :
Excess of the Length of day for the last years :
Look at their atmospheric excitation
The Paris Observatory is hosting two components of The International Earth Rotation Service: the Earth Orientation and International Celestial Reference Frames Centers, in close association with the International Terrestrial Reference Frame Center, hosted in Institut Géographique National, located in Ile de France. The International Earth Rotation Service (IERS) is an interdisciplinary service that maintains key connections between astronomy, geodesy and geophysics. He provides:
Celestial reference frame Terrestrial reference frame Earth orientation data Permanent information on the Earth fluid layer IERS ConventionsThe service now accomplishes its missions through various components: a Central Bureau, Techniques Centers, Product Centers and Combination Research Centers.