Calculates the parameter of the Precession.
[z_A, theta_A, zeta_A] = par_praezession(t_j2k)
time in the epoch J2000.0
z_A [decimal degree]
theta_A [decimal degree]
zeta_A [decimal degree]
Calculates the parameter of the Precession.
Precision: ca. 1''
(matrix aware).
No warranty, there are no inputchecks.