I was unable to locate a thread whose title referred to the column about the Star of Bethlehem being a “conjunction,” or whatever. So I’ll take it up in a separate thread.
Near as I have been able to determine, the accepted belief is that Jesus was born in 6 B. C., or thereabouts, extrapolating from the chronology given in the Gospels along with the commentary by translator William Whiston, in Antiquities of the Jews, compiled by first-century Jewish historian Flavius Josephus. For various reasons Whiston concludes that Jesus would have to have been born in 4 B. C., or 6 B. C., given the “two years” reckoning used by Herod the Great in ordering the slaughter of boys, one of whom might be the “usurper” of his throne. 
There are, however, a number of inconsistencies in Josephus’ works; it’s not something I can automatically blame on Whiston. By another line of reckoning from Josephus’ works one could come to the year 1 B.C., or even A.D. 1. In fact, for various reasons, which I will post here if asked, it is likely that He was born in fact in early October of 2 B.C.–notwithstanding Josephus, Whiston, or the scene in Back to the Future in which Lloyd’s time machine is set, for example, to “12-25-00.”
Are you referring to the mailbag item What’s up with the star of Bethlehem? (10-Mar-2000)
So why would Jesus be born in 2 B.C.? Are these reasons related to astronomy?
Since this is a Mailbag item, not one of Cecil’s columns, I am moving this to the forum COMMENTS ON MAILBAG QUESTIONS.