Precession-Nutation

Astronomical determination of the Earth's dynamical flattening using VLBI observations and IAU 2006/2000 Precession-Nutation Model
VLBI celestial pole observations provide a consistent estimate of the Earth’s dynamical flattening for precession and nutation and recover long-term J₂ variations broadly consistent with satellite laser ranging.
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Astronomical determination of the Earth's dynamical flattening using VLBI observations and IAU 2006/2000 Precession-Nutation Model