A note on the numerical expressions for precession calculations

Details A note on the numerical expressions for precession calculations A note on the numerical expressions for precession calculations

Nov 1981

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1981a%26a...103..103b&link_type=abstract

Astronomy and Astrophysics, vol. 103, no. 1, Nov. 1981, p. 103-107. In French.

Physics

16

Celestial Mechanics, Numerical Integration, Precession, Solar Physics, Stellar Motions, Ephemerides, Reference Systems, Solar Rotation

Scientific paper

The precession quantities are completely determined by the two motions of the equatorial pole and the ecliptic pole. The precessional formulae derived by (Lieske et al., 1977) are based upon the use of the secular variations of the ecliptic pole from Newcomb's theory of the Sun. Taking advantage of the analytic formular given by Lieske et al., the authors propose new expressions for the precession quantities, gathered in Table 1, setting up the secular motion of the ecliptic pole from Bretagnon's theory of the Sun, which has been developed up to the third order of planetary masses.
First, we discuss the proposed expressions for precession quantities, computed with the new value of general precession ρ1, and the obliquity ɛ0, at the epoch J2000, recommended by IAU. We emphasize the fact that precession quantities introduced in the ephemerides should be consistent with the Sun's theory which is used. Finally, one justifies this proposal for these new precessional quantities by the correctness of the C and s functions of formulae (2). The digits in formulae (3) will not be modified by a fourth order planetary perturbation, as well as by a slight modification of the integration constants in Sun's theory, which has been fitted to observations via modern numerical integrations.
Secondly, we present the results of a comparison of Bretagnon's theory of the Sun with the JPL numerical integration DE 102. Referring to the internal reference frame of DE 102 (equator and equinox 1950), we compute the shift of the vernal equinox:
ΔφFK4(1950) = -0".2300
and evaluate the obliquity:
ɛ102(1950) = 23°26'44".813.
Using a rotation matrix proposed by Standish to refer the DE 102 coordinates with respect to FK4, we then determine the two quantities:
ΔφFK4(1950) = -0".6472
ɛFK4(1950) = 23°26'44".814.
ΔφFK4 corresponds to an equinox offset of E = 0".5536. Again, ɛ0 is evaluated for the epoch J2000. We find:
ɛ0(2000) = 23°26'21".409.

Affiliated with

Also associated with

No associations

Rating

A note on the numerical expressions for precession calculations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with A note on the numerical expressions for precession calculations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A note on the numerical expressions for precession calculations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-743232