co_nutate {astrolibR}R Documentation

Calculate changes in right ascension and declination due to nutation of the Earth's rotation

Description

Calculate changes in right ascension and declination due to nutation of the Earth's rotation

Usage

co_nutate(jd, ra, dec)

Arguments

jd

Julian Date [scalar or vector]

ra

right ascension, in degrees (scalar or N-vector)

dec

declination, in degrees (scalar or N-vector)

Details

Calculates necessary changes to right ascension and declination due to the nutation of the Earth's rotation axis, as described in Meeus (1991), Chap 23. Uses formulae from the Astronomical Almanac (1984) and does the calculations in equatorial rectangular coordinates to avoid singularities at the celestial poles.

Value

d_ra

corrections to ra due to aberration, in arcseconds (must then be added to ra to get corrected values).

d_dec

corrections to dec due to aberration, in arcseconds (must then be added to dec to get corrected values).

eps

true obliquity of the ecliptic, in radians

d_psi

nutation of the longitude of the ecliptic

d_eps

nutation in the obliquity of the ecliptic

Author(s)

Written Chris O'Dell (2002)

R adaptation by Arnab Chakraborty (June 2013)

References

Meeus, J., Astronomical Algorithms, Willmann-Bell, 1991

See Also

nutate

Examples

co_nutate(2456469.5,253.215,-32.449)

[Package astrolibR version 0.1 Index]