public function calculateEccentricAnomaly($averageAnomaly, $eccentricity, $decimale = 7) {

        $previous = 0;

        $ea       = $averageAnomaly;

        $z =0;

        while ($ea != $previous && $z < 10000) {

            $previous = $ea;

            $ea       = self::roundness($averageAnomaly + $eccentricity * sin($ea), $decimale);

            $z++;

        }

        echo '$z = '.$z.'<br/>';

        return $ea;