co_nutate:
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)
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
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.