public static function jdToJulian($julian_day)
    {
        // PHP has different limits on 32 and 64 bit systems.
        $MAX_JD = PHP_INT_SIZE == 4 ? 536838829 : 784368370349;

        return self::jdToCalendar(self::$julian_calendar, $julian_day, 1, $MAX_JD);
    }