palFk54z palFk54z - Convert a J2000.0 FK5 star position to B1950.0 FK4 assuming zero proper motion and parallax

Description:
This function converts star positions from the IAU 1976, FK5, Fricke system to the Bessel-Newcomb, FK4 system.

Invocation:
palFk54z( double r2000, double d2000, double bepoch, double $*$r1950, double $*$d1950, double $*$dr1950, double $*$dd1950 )

Arguments:

r2000 = double (Given)
J2000.0 FK5 RA (radians).
d2000 = double (Given)
J2000.0 FK5 Dec (radians).
bepoch = double (Given)
Besselian epoch (e.g. 1950.0).
r1950 = double $*$ (Returned)
B1950 FK4 RA (radians) at epoch "bepoch".
d1950 = double $*$ (Returned)
B1950 FK4 Dec (radians) at epoch "bepoch".
dr1950 = double $*$ (Returned)
B1950 FK4 proper motion (RA) (radians/trop.yr)).
dr1950 = double $*$ (Returned)
B1950 FK4 proper motion (Dec) (radians/trop.yr)).

Notes: