There are several problem with the the Star of Bethlehem to have been a conjunction. First, Matthew informs us that the Star appeared. Conjunctions do not appear. If you know what they are, you know that it takes time for the objects to line up. Therefore, the Magi would not have lost track of the Star only to have it "reappear" to them after meeting with Herod. Second, Babylonians were reading horoscopes around the time of Jesus, and could have read a conjunction into a horoscope. But, if the Magi were from Parthia, which is more likely, they did not have the technology yet to follow conjunctions. Ancient horoscopes in general were more for living important people, and not as a future prophecy for an unknown leader to be. If they did there is no known evidence for this, if there is I have not found it, and would like to see it. Many proponents of conjunction just assume the ancients had this technology, so they did it. But, as a historian I want to see actual sources from the time that prove conjunctions were uses as used for prophecy. As for today, some Christians have used conjunctions to predict prophecy and end times discourse. I do not, and do not understand how this fad started. Nowhere in the Bible or Talmud are conjunctions used to predict or warn the people. Prophecy given by God to the Jews was done through dreams, angles, or God directly speaking to people, and never through interpretations of conjunctions. But, today some are using the signs in the heavens to justify current or future events. The alignment of Jupiter and Venus are not signs from God, only natural occurrences. But, people can use the flexibility of conjunctions to proclaim them as "signs" for the second coming of Jesus or events from Revelation.
Problems with Rick Larson"s theory:
According to Larson, a triple conjunction started on September 11, 3 BCE, which he believes is the Conception of Jesus. This is the first meeting of Jupiter and Regulus (looking east). Regulus is the brightest star in Leo and thought to be very special. The nation of Israel is often referred to as the “Lion of Judah,” so this meeting would have been important. Then, nine months (the duration of a pregnancy) later, on June 17, 2 BCE, Jupiter and Venus (the planet of mothers) met in Leo (over Israel this would have been in the west), and it would have been a very bright “star” indeed. This would have marked the birth of Jesus. Then on December 25, 2 BCE, if you were in Jerusalem looking south toward Bethlehem, Jupiter would be “standing” in Virgo, the constellation of the Virgin (Mary being a virgin). Larson believes that this was the day the Magi would have visited the baby Jesus.
Major flaws here include; First, many nations are represented by lions, its too easy to speculate. Second, most historians agree that Herod died in 4 BCE, thus Jesus could not have been born after that. Third, Herod's sons date the beginning of their reigns as 4 BCE. Herod, a mega-manic, would not have shared his reign with anyone. His sons would have to wait for him die. Finally, there are no primary sources from this time that mention anything special about the 3 BCE alignment. I know many Christians have watched Larson's documentary have been inspired by it, but his research is not valid, and way too much speculation is involved for any real historian to use.
14 years ago I became interested in the date that Jesus was born. This led to several years of research, I quickly realized that there was no valid information that provided any real answers to this question. Since this website is getting some interest I will post from time to time some of the information I learned during this quest.