## 2. Notations and constantsThe notations are the same as in Bretagnon et al. (1997). The unit of time is one thousand Julian years (tjy). The following constants are taken from the numerical integration of the JPL DE403/LE403 (Standish et al., 1995) and from the IERS Standards 1996 (IERS, 1996). Value of the astronomical unit: Equatorial radius of the Earth: We note , , the masses of the Sun, the Earth and the Moon. From DE403/LE403 we take From the value of the Gaussian gravitational constant and from the mass of the Earth, we compute The geopotential coefficients are computed
from the GEM-T3 model given by the IERS Standards 1992 (IERS, 1992).
The longitude of the major axis of the equatorial ellipse
corresponding to the principal moment of inertia The constants depending of the precision of the solution, like principal moments of inertia, have slight modifications. So, to obtain the William's (1994) value of the constant of the general precession /tjy, the equations of Sect. 3 must be solved to yield We thus obtained The dynamical ellipticity is The values of the moments of inertia The linear part of the angle measuring the rotation of the Earth is with For the obliquity we take the angle between the rotational equator J2000 and the inertial dynamical ecliptic J2000: © European Southern Observatory (ESO) 1998 Online publication: November 24, 1997 |