Convert to an ``A.D. 2014-Jan-18 01:35:37.5000 UT`` string.

        Returns a string for this date and time in UTC, in the format
        used by the JPL HORIZONS system.  If this time is an array of
        dates, then a sequence of strings is returned instead of a
        single string.

def utc_jpl(self):
        """Convert to an ``A.D. 2014-Jan-18 01:35:37.5000 UT`` string.

        Returns a string for this date and time in UTC, in the format
        used by the JPL HORIZONS system.  If this time is an array of
        dates, then a sequence of strings is returned instead of a
        single string.

        """
        offset = _half_second / 1e4
        year, month, day, hour, minute, second = self._utc_tuple(offset)
        second, fraction = divmod(second, 1.0)
        fraction *= 1e4
        bc = year < 1
        year = abs(year - bc)
        era = where(bc, 'B.C.', 'A.D.')
        format = '%s %04d-%s-%02d %02d:%02d:%02d.%04d UT'
        args = (era, year, _months[month], day, hour, minute, second, fraction)

        if self.shape:
            return [format % tup for tup in zip(*args)]
        else:
            return format % args