Home > Concepts, Conjunction, Ephemeris Program > 12/19/2017 – Ephemeris – Were celestial events in 7 BC interpreted as the Star of Bethlehem?

12/19/2017 – Ephemeris – Were celestial events in 7 BC interpreted as the Star of Bethlehem?

December 19, 2017

Ephemeris for Tuesday, December 19th. The Sun will rise at 8:15. It’ll be up for 8 hours and 49 minutes, setting at 5:04. The Moon, 1 day past new, will set at 6:34 this evening.

This year we have no bright evening Christmas star. But what about the one described in the Bible, in the gospel of Luke? We will look today at the first of two events that may have been recorded as the Star of Bethlehem. In 7 BC there was a rare event over 6 months when three times the planet Jupiter passed Saturn against the stars of the constellation Pisces. Could the Persian astrologer priests called Magi, have read into the event enough significance to start the journey to Jerusalem in search of the new born King of the Jews? It was the scribe’s readings that then sent them to Bethlehem. It is thought that Pisces was associated with the Hebrews, Jupiter with the Messiah or world ruler, and Saturn with the peoples of Palestine.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.


Triple conjunction

The Jupiter-Saturn triple conjunction of 7 BC. Click on the image to enlarge. Created using Cartes du Ciel.

The animation above shows the planets at 5 day intervals in 7 and a bit in 6 BC.  The normal or posigrade motion is toward the east or left.  When an outer planet approaches its opposition from the Sun, it seems to slow and reverse direction and head westward for a time, which is retrograde motion.  After a time it reverses and heads back eastward again.  That’s why the planets seem to see-saw back and forth.  Jupiter passes Saturn every 20 years.  The next time will be in 2020.  On my Wednesday planet charts Jupiter is seen sneaking up on Saturn week by week.  In order to have three conjunctions instead of one, the planets need to be near opposition from the Sun when they pass.  The last time that happened was in 1980, but it wasn’t against Pisces.  Triple conjunctions against a particular zodiacal constellation are much rarer.

The dates for key events in the animation above are:

  • First Conjunction May 29, 7 BC
  • Planets are Stationary July 6, and begin retrograde motion
  • Second Conjunction October 11
  • Planets are Stationary November 1 and resume posigrade motion
  • Third Conjunction on December 8
  • Mars joins February 26, 6 BC

Retrograde motion was difficult to explain when one thinks that the Earth is the center of the Universe and stationary, while the planets supposedly orbited in perfect uniform circular motion around it.  It’s easy when the Earth is a moving planet like the rest.  When an outer (superior) planet is at opposition from the Sun.  The Earth is between the Sun and planet and moving faster.  So we’re passing the outer planet.  When you are in a car passing another, the car being passed seems to move backward with respect to your car.  Since the planets orbits are like a race track, we get to lap the outer planets at regular intervals.

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