Great conjunction

A Great Conjunction is a conjunction of the planets Jupiter and Saturn. The last Great Conjunction took place on May 31, 2000, while the next one will be in late December 2020. Great Conjunctions take place regularly, every 18–20 years, as a result of the combined ~12-year orbital period of Jupiter around the Sun, and Saturn's ~30-year orbital period. The 2000 conjunction fell within mere weeks after both had passed conjunction with the Sun, and it was very difficult to observe without visual aid because the two planets rose only 30–45 minutes before sunrise, depending upon the location of the observer.

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Greatest conjunction

Greatest conjunction is a conjunction of Jupiter and Saturn at or near their opposition to the Sun. In this scenario, Jupiter and Saturn will occupy the same position in right ascension on three separate occasions over a period of a few months.

The so-called "Star of Bethlehem" — thought to have appeared c. 7 BC — was theorized to be a greatest conjunction; and some went so far as to assert that it was an occultation of Saturn by Jupiter, with the two planets appearing to merge into a single object as seen from Earth. However such an event did not take place at historic times. At the greatest conjunction in 7 BC, which is said to be the "Star of Bethlehem",[1] the minimum distance between Jupiter and Saturn was around 1 degree, this is twice the Moon's diameter. The next occultation of Saturn by Jupiter will take place in 7541.

There is no obvious period for the occurrence of greatest conjunctions: the last greatest conjunctions took place in 1682/83, 1821 (only in right ascension), 1940/41 and 1981, while the next one will take place in the year 2238/39.

Great Conjunctions in Right ascension between 1800 and 2100

Date Time UTC Planet Angle distance Planet Elongation to sun
July 21, 1802 03:22:00 Jupiter 42' south of Saturn 37.9° East
June 25, 1821 00:05:09 Jupiter 1°15' north of Saturn 67.5° West
November 22, 1821 23:49:55 Jupiter 1°20' north of Saturn 140.2° East
December 23, 1821 09:28:49 Jupiter 1°22' north of Saturn 108.5° East
January 25, 1842 22:22:31 Jupiter 32' south of Saturn 26.8° West
October 25, 1861 15:11:20 Jupiter 52' south of Saturn 43.1° West
April 22, 1881 11:58:20 Jupiter 1°18' north of Uranus 1.0° East
November 28, 1901 06:10:38 Jupiter 27' south of Saturn 38.6° East
September 14, 1921 16:22:08 Jupiter 1°02' south of Saturn 6.2° East
August 15, 1940 13:18:42 Jupiter 1°15' north of Saturn 97.5° West
October 11, 1940 23:17:26 Jupiter 1°17' north of Saturn 155.0° West
February 20, 1941 19:14:02 Jupiter 1°21' north of Saturn 67.7° East
February 18, 1961 14:42:37 Jupiter 14' south of Saturn 34.6° West
January 14, 1981 07:58:37 Jupiter 1°09' south of Saturn 103.9° West
February 19, 1981 07:12:10 Jupiter 1°09' south of Saturn 141.2° West
July 30, 1981 21:32:22 Jupiter 1°12' south of Saturn 57.9° East
May 31, 2000 10:13:27 Jupiter 1°11' north of Saturn 16.9° West
December 21, 2020 13:48:52 Jupiter 6' south of Saturn 30.3° East
November 5, 2040 13:19:46 Jupiter 1°14' south of Saturn 24.8° West
April 10, 2060 09:01:25 Jupiter 1°09' north of Saturn 39.8° East
March 15, 2080 08:29:24 Jupiter 6' north of Saturn 43.8° West
September 24, 2100 01:40:38 Jupiter 1°18' south of Saturn 25.1° East

Great Conjunctions in ecliptical longitude between 1800 and 2100

Date Time UTC Planet Angle distance Planet Elongation to sun
July 17, 1802 22:57:00 Jupiter 39' south of Saturn 40.6° East
June 19, 1821 16:56:57 Jupiter 1°10' north of Saturn 63.3° West
January 26, 1842 06:16:53 Jupiter 32' south of Saturn 27.1° West
October 21, 1861 12:27:02 Jupiter 48' south of Saturn 39.7° West
April 18, 1881 13:35:59 Jupiter 1°13' north of Saturn 3.1° East
November 28, 1901 16:37:33 Jupiter 26' south of Saturn 38.2° East
September 10, 1921 04:13:03 Jupiter 57' south of Saturn 9.7° East
August 8, 1940 01:13:20 Jupiter 1°11' north of Saturn 90.9° West
October 20, 1940 04:42:14 Jupiter 1°14' north of Saturn 164.0° West
February 15, 1941 06:36:25 Jupiter 1°17' north of Saturn 72.9° East
February 19, 1961 00:07:18 Jupiter 14' south of Saturn 34.9° West
December 31, 1980 21:17:24 Jupiter 1°03' south of Saturn 90.9° West
March 4, 1981 19:14:36 Jupiter 1°03' south of Saturn 155.9° West
July 24, 1981 04:13:35 Jupiter 1°06' south of Saturn 63.8° East
May 28, 2000 15:56:27 Jupiter 1°09' north of Saturn 14.9° West
December 21, 2020 18:37:31 Jupiter 6' south of Saturn 30.1° East
October 31, 2040 12:02:47 Jupiter 1°08' south of Saturn 20.8° West
April 7, 2060 22:36:24 Jupiter 1°07' north of Saturn 41.9° East
March 15, 2080 01:49:55 Jupiter 6' north of Saturn 43.5° West
September 18, 2100 22:50:40 Jupiter 1°13' south of Saturn 29.4° East

Great Conjunctions and History

Great conjunctions are less spectacular than eclipses or comets but nevertheless they have also attracted considerable attention as celestial omens. During the late Middle age and the Renaissance they became a rather popular topic broached by most astronomers of the period up to the times of Tycho Brahe and Kepler, by scholastic thinkers as Roger Bacon [2]or Pierre d'Ailly[3], and they are mentioned in popular and literary writing by authors such as Dante [4] or Shakespeare[5]. This interest is traced back in Europe to the translations from Arabian sources, most notably Albumasar's book on conjunction[6].

As successive great conjunction occur nearly 120° apart, their appearances form a triangular pattern. In a series every fourth conjunction returns after some 60 years in the vicinity of the first. These returns are observed to be shifted by some 7-8°, so no more than four of them occur in the same zodiacal sign. To each sign astrologers have ascribed one from the series of four elements and thus four triplicities or 'trigons' are formed. Particular importance has been accorded to the occurrence of a great conjunction in a new trigon, which is bound to happen after some 200 years at most[7]. Even greater importance was attributed to the beginning of on new cycle after all fours trigons had been visited, something which happens in about 800 years.

Originally a trigon was thought to last 240 years and the full cycle 960 years but later more correct estimation were provided by the Alphonsine tables[4]. Despite the inaccuracies and some disagreement about the beginning of the cycle the belief in the significance of such events generated a stream of publications which grew steadily up to the end of the 16th c. As the great conjunction of 1583 was the last in the watery trigon it was widely supposed to herald apocalyptic changes; a papal bull against divinations was issued in 1586 and as nothing really significant had happened by 1603 with the advent of a new trigon, the public interest rapidly died.

References

  1. ^ Michael R. Molnar: The Star of Bethlehem: The Legacy of the Magi, Rutgers University Press, 1999
  2. ^ The Opus Majus of Roger Bacon, ed. J. H. Bridges, Oxford:Clarendon Press, 1897, Vol. I, p. 263.
  3. ^ De concordia astronomice veritatis et narrationis historice (1414) [1]
  4. ^ a b Woody K., Dante and the Doctrine of the Great Conjunctions,Dante Studies, with the Annual Report of the Dante Society, No. 95 (1977), pp. 119-134
  5. ^ Aston M., The Fiery Trigon Conjunction: An Elizabethan Astrological Prediction, Isis, Vol. 61, No. 2 (Summer, 1970), pp. 158-187
  6. ^ De magnis coniunctionibus was translated in the 12th c., a modern edition-translation by K. Yamamoto and Ch. Burnett, Leiden, 2000
  7. ^ Etz D., (2000), Conjunctions of Jupiter and Saturn, Journal of the Royal Astronomical Society of Canada, Vol. 94, p.174 [2]

See also