public static function Ee00b($date1, $date2) {
    $dpsipr;
    $depspr;
    $epsa;
    $dpsi;
    $deps;
    $ee;

    /* IAU 2000 precession-rate adjustments. */
    IAU::Pr00($date1, $date2, $dpsipr, $depspr);

    /* Mean obliquity, consistent with IAU 2000 precession-nutation. */
    $epsa = IAU::Obl80($date1, $date2) + $depspr;

    /* Nutation in longitude. */
    IAU::Nut00b($date1, $date2, $dpsi, $deps);

    /* Equation of the equinoxes. */
    $ee = IAU::Ee00($date1, $date2, $epsa, $dpsi);

    return $ee;
  }