There has been a number of articles and internet postings written as of late about how the upcoming conjunction of Jupiter and Saturn may of been the Star of Bethlehem. Although we can't be sure it seems extremely unlikely.
According to an article on Space.com written by Joe Rao on December 23, 2011, the article states the "possibility is one or more of the bright naked-eye planets [was the Star of Bethlehem]. The likelihood that the Magi could have confused one or more of the familiar planets with a star seems remote. However, sometimes two or more of these restless wanderers come together in a striking conjunction.
Perhaps a planetary grouping of particular beauty; an exceptionally close conjunction of two planets or groupings of three or more creating an eye-catching geometric figure in the sky may have taken place between the years 7 and 2 B.C. Such a gathering would be quite unusual to say the least.
One such event that we've already mentioned occurred in 6 B.C. involving Mars, Jupiter and Saturn, and happened in the constellation of Pisces, the Fishes.
Yet another possible explanation for the Star of Bethlehem is the three-times passing of Jupiter and Saturn between May and December in 7 BC; a rare triple or "great conjunction." Jupiter appeared to pass one degree north of Saturn on May 29; practically the same on Sept. 30; then finally a third time on Dec. 5.
There is no doubt about the visibility of these events, mostly opposite to the sun in nighttime skies. As for their astrological impact, the Magi would have certainly noticed that both planets did not appear to separate widely between their conjunctions. In fact, for eight consecutive months – the time it might have taken to travel the 500 miles or more from Babylonia to Judea – Jupiter and Saturn remained within three degrees of each other, from late April of 7 B.C. until early January of 6 B.C.
But perhaps no other planetary grouping can equal that of the two brightest planets – Venus and Jupiter – for the explanation that we seek. And if we take the only known account of the Star given in St. Matthew, then what we really need is the appearance of not just one, but two "stars." The first appearance would have been seen well in advance of the Magi’s arrival in Bethlehem, and the other at the end of their long journey.
Maybe the signal for their star was to be a sign in the constellation of Leo, the Lion.
To the early Israelites, Leo was a constellation of great astrological significance and considered a sacred part of the sky. A very close conjunction of Venus and Jupiter would have been visible in the eastern dawn sky of the Middle East on August 12, 3 B.C.
When they first emerged above the eastern horizon, the two planets were separated by only about two-fifths of the moon's apparent diameter or 12 minutes of arc. As a comparison, the separation of the stars Mizar and Alcor in the handle of the Big Dipper is also 12 arc minutes.
Planets this close can be very striking, if they don't differ too much in brightness. Incidentally, this sign would have been both seen "in the east" by Persian men "in the East," explaining the ambiguous phrase in St. Matthew.
Venus ultimately vanished into the glare of the sun, but Jupiter and Leo remained in the night sky during the next ten months. During this time a number of additional planetary conjunctions took place, all of which would have been of great importance to the priest-astrologers of the time.
Sometime during the spring of 2 B.C. the Magi might have had their audience with King Herod, who questioned them diligently as to what they had seen and when. Obviously Herod and his advisers missed out on seeing the "star" for themselves (but then again, it appeared at around 4 or 5 a.m. when likely the only thing they were watching were the inside of their eyelids!). Herod sent the Magi on their way to search for the Christ child.
Then, during June of 2 B.C., as Jupiter and the stars of Leo began to sink into the western evening twilight, Venus again returned to this same region of the sky for an even more spectacular encore. The Magi certainly would have especially taken note that on the evening of June 17, Jupiter and Venus appeared even closer together than they did in the dawn skies of the previous August.
As the planets slowly descended toward the horizon they got closer and closer together. Finally, at 8:30 p.m. local time they drew to within a mere 0.6 of an arc minute of each other while appearing in the western twilight sky.
To the Magi the two brightest planets must have appeared to coalesce into one and glowed before them like a dazzling beacon over Judea. Eyeglasses were many centuries in the future, so only people with perfect eyes would have seen the planets separated.
Astronomy can tell us that all these planetary conjunctions indeed occurred. But whether anyone actually observed them, and if any of these sent the Magi on their historic journey, are all matters for conjecture."
The article also states "the simplest answer is a nova or supernova outburst: A new star blazes forth where none had ever been seen and leaves no trace for us to find in the future." "Most bright novas suddenly and unexpectedly flare into prominence literally overnight, attracting the instant attention of sky-conscious people. But after several days or weeks of such prominence, it gradually fades back to obscurity." "Although a nova or supernova is the most satisfying explanation for the Star, there is a serious problem with it, in that there doesn't seem to be any definitive record of a bright nova appearing in the sky during the time that biblical historians believe the Magi made their journey. One nova apparently did appear, bordering the constellations Capricornus and Aquarius during the spring of 5 B.C. But the Chinese records, which describe this object, imply that it was apparently not very conspicuous at all."