Re:The Dec 21, 2020 Conjunction of Jupiter and Saturn
by antognini on Saturday December 05, 2020 @02:30PM
(#25317537)
In addition to that, while Kepler was lecturing on the Great Conjunction he was drawing the trigon [1] which shows how the locations of Great Conjunctions change over time. This drawing (consisting of a triangle inscribed inside a circle that gets shifted over time), inspired him to pursue the idea that the distances to the planets were determined by polygons of different shapes inscribed in circles. This didn't work, so he moved on to Platonic solids, which worked better, but still not perfectly. Eventually this pursuit lead him to the idea of describing the planetary orbits by ellipses.
[1]: https://en.wikipedia.org/wiki/Great_conjunction#/media/File:...
> When studying the great conjunction of 1603, Johannes Kepler thought that the Star of Bethlehem might have been the occurrence of a great conjunction. ... A triple 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 (or ecliptic longitude) on three occasions (due to apparent retrograde motion) over a period of a few months.
Presumably the significance of a triple conjunction is that it explains the story of the Magi seeing a "star in the East", which then "troubled" Jerusalem when they arrived there, until it "went before them", and then finally "stood over where the young Child was".[1]
[0] https://en.wikipedia.org/wiki/Great_conjunction#%E2%88%926
[1] https://www.biblegateway.com/passage/?search=Matthew+2%3A1-1...