fw2xy, gamma_bar, phi_bar, psi, eps,
[SOFA] Returns CIP
y, given the
Fukushima-Williams bias-precession-nutation angles
eps. All of the input and output parameters are measured
in radians. They all have the same dimensions.
e is the J2000.0 ecliptic pole,
p is the GCRS pole,
e is the ecliptic pole of the date, and
p is the CIP,
then the four Fukushima-Williams angles are:
gamma_bar = epE,
phi_bar = pE,
psi = pEP, and
eps = ep.
See also: Astronomical Coordinate Calculations