'Compute and return the precession matrix for FK5 based on Capitaine et
al. 2003/IAU2006.  Used inside some of the transformation functions.
Parameters
oldequinox : `~astropy.time.Time`
The equinox to precess from.
newequinox : `~astropy.time.Time`
The equinox to precess to.
Returns
newcoord : array
The precession matrix to transform to the new equinox'

@staticmethod
def _precession_matrix(oldequinox, newequinox):

    return earth.precession_matrix_Capitaine(oldequinox, newequinox)
