One theory speaks of the Jupiter-Saturn triple conjunction of 7 BCE when the two planets appeared to be near each other in May, September, and December. They appeared at that time in the constellation Pisces, which at that time was associated with the Hebrews. The second of the conjunctions would have convinced the Magi to set out. The third would have occurred as they reached Bethlehem. This date would fit the account of Flavius Josephus in Antiquities of the Jews.
There is mention of a lunar eclipse to fit the above theory and one to fit another theory. This one would bring the birth of Jesus to 3 or 2 BCE. There was another conjunction, more brilliant, this time involving Jupiter and Venus. This took place in the constellation Leo. An amulet dating to shortly afterwards shows a lion with a star at his feet.
All experts agree that the word “star” in the Bible can refer to a planetary conjunction, a comet, or other celestial phenomena. Since the Chinese astrologers, who kept accurate records, did not mention anything sensational occurring at the time, a nova or a supernova has been ruled out.