Originally published in The Observatory, Vol. 118, No. 1142, pp. 22-24, 1998 February

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Lunar Occultations of Jupiter and Saturn, and the Star of Bethlehem

Molnar1 has presented a detailed case for his proposal that the Magi's star, or star of Bethlehem of the New Testament gospel of St. Matthew2, may be identified with a pair of astrologically significant lunar occultations of Jupiter in Aries on 6 BC March 20 and April 17. Here, we report the identification of further contemporary astronomical events, a pair of occultations of Saturn in Pisces, which may be capable of astrological interpretation as ``omens'' supporting Molnar's hypothesis. We also show that Molnar's model horoscope for the birth of Christ requires a remarkably rare set of circumstances.

Molnar's argument depends not just on the fact of an occultation of Jupiter (which is a relatively common occurrence), or even on a pair of occultations, but on the astrological interpretation of the first occultation being within the terms of Jupiter in Aries--a technical terminology meaning that Jupiter's precise position within Aries amplified its own influence and especially the powerful influence of an occultation. The presence of Mars in Aries was a further a priori requirement for his identification. Aries was traditionally associated with Judaea and surrounding areas, according to the Tetrabiblos of Claudius Ptolemy (see ref. 1). The presence of an astrological device, the Lot of Fortune, in the same part of the zodiac as the first occultation is also crucial to his identification of these events as the Magian star. He showed that similar horoscopes in the Magian or Chaldaean system had been described in ancient times for Roman emperors such as Augustus, Tiberius, and Hadrian.

Molnar's suggested identification of the star of Bethlehem also fits a circumstance described by St. Matthew: the Magi came to Judaea believing that a king had been born, but Herod's advisors, who did not practise astrology, had not seen the portent because it took place at a time when it would have been invisible, and would therefore have been known only to astrologers. Molnar proposed a new interpretation of the account of the Magi seeing the star ``in the east,'' a phrase that has had many suggested interpretations but which can be read in its astrological meaning ``at the rising''. But the Greek phrase could be a common ancient mistake for the technical term meaning ``at heliacal rising'' or rising with the Sun. Finally, Molnar observed that the second occultation, although it did not take place in the terms of Jupiter in Aries, nevertheless would have provided a confirming omen to the Magi because it took place in the general direction of Bethlehem as seen from their location in Jerusalem.

Molnar argued that the Magi (``wise men'') were astrologers who were able to predict the occultations from their observations of the Moon and empirical knowledge of its complicated path. Such occultations, he pointed out, were particularly significant astrological events, especially in association with certain configurations and heliacal risings, even if they were invisible to the eye because they took place after setting or during the middle of the day. In Magian astrology, the importance of a lunar conjunction was dependent on the proximity of the Moon to the other object, with an occultation being a particularly powerful form of close conjunction.

Out of curiosity, we reviewed the astronomical events of 6BC with two commercially available PC packages3,4. The results confirm fully Molnar's descriptions of the two occultations. But in the course of this diverting exercise we noticed two other events which, to the best of our knowledge, have not been previously mentioned: on the calendar day before each occultation of Jupiter, the Moon also occulted Saturn in Pisces. The first occultation of Saturn took place on March 19, 22.20 - 22.30 local Jerusalem time4, i.e., after the planet had set and about 19 hours before the first occultation of Jupiter on March 20; the Moon occulted Saturn again on April 16, 10.51 - 12.09 local Jerusalem time4, about 25 hours before the second occultation of Jupiter. We consider the viewpoint of Jerusalem (or at least, the viewpoint of the Middle East) to be of some importance in this discussion because the lunar parallax would render the occultations of Jupiter and Saturn into conjunctions if they were observed from other, distant parts of the Earth.

Saturn's astrological significance is also well documented. In Humphreys' discussion 5 of the possible identification of the star of Bethlehem as a comet recorded by Chinese astronomers in the spring of 5 BC, it is noted that in Magian astrology Saturn represented the divine Father and Jupiter his son. Furthermore, according to late Mediaeval Jewish sources, Pisces was associated with the Jewish people. We note, though, that Molnar cautioned the reader that interpretations such as this may have changed over 1500 years.

Although Molnar did not specify uniqueness as one of his criteria, the expected rarity of Molnar's a priori model horoscope for Christ can be estimated. We used Dance of the Planets (reference 3) to calculate every lunar occultation above the horizon from the region of Jerusalem over a sample period of 2000 years (-1050 to +950). There were 369 single occultations and 42 double occultations ( i.e., one month apart). Of the latter, only three were in Aries (one of which was Molnar's event) and two more were ``near misses.'' It would seem from this limited sample that such double occultations occur about twice a millennium in any given zodiacal sign. However, Mars is present in Aries only for 1/12 of the time, on average, so such a rare combination of events would occur about once every 6000 years. If one relaxed the criteria to seek only single occultations of Jupiter in Aries with Mars in the same sign, the average frequency would be once in 780 years, still quite a rare event. Therefore, we conclude that the occurrence of astrological events with the right general properties would have been rare enough (separated by 1-2 millennia) to have been unique in the experience and lore of the Magi.

At the time of the second saturnian occultation, both codes agree that the planet was well within one degree of the first point of Aries. In other words, at its occultation and that of Jupiter which followed, Saturn was in Pisces and about to enter the sign of Aries, which was associated with Judaea by the traditions of the era. Molnar pointed out that the occultation of Jupiter on April 17 would have occurred in a southwesterly direction as seen from Jerusalem, about 30° from the azimuth of Bethlehem, and suggested that---given the vagaries of the Judaean road system---this was close enough to have impressed the Magi as a powerful confirmation6 . We note that the occultation of Saturn on the previous day would actually have bracketed (188-218°) the true azimuth of Bethlehem (~195°) as seen from Jerusalem. We speculate that this may also be relevant to the literal interpretation of the star having ``stood over where the young child was''. Unlike ordinary celestial objects, which move through the sky with the Earth's diurnal rotation, an occultation lasting of the order of one hour can only take place in a narrow range of directions as seen from any single location.

We are not experts on Magian astrology or on Biblical exegesis, and are unwilling to assign definitive astrological, mystical, or religious import to our results. We leave it to others to interpret such shades of meaning, and to consider whether the remarkable events of 6 BC March 19--20 and April 16--17 lend further support to Molnar's proposed identification of the star of Bethlehem. We thank the referee, Dr. D. Hughes, for his comments on an earlier version of this letter.

Yours faithfully,

M.M. Dworetsky and S.J. Fossey


e-mail: mmd@star.ucl.ac.uk , sjf@star.ucl.ac.uk

1997 November 19

(1) M.R. MOLNAR, QJRAS, 36, 109, 1995.
(2) BOOK OF MATTHEW, 2, 1.
(5) C.J. HUMPHREYS, QJRAS, 32, 389, 1991.
(6) BOOK OF MATTHEW, 2, 9.