That is a good question, John.
As bright as Aldebaran is, its appearance is relatively constant to observers on earth. This means it would have appeared as it always has and would not have triggered any extra notice from people.
The great astronomer and astrologer Johannes Kepler theorized in 1614 that the "Star of Bethlehem" may have been the conjunction of Jupiter and Saturn in 7 BC. We now know that this conjunction was never within 1 degree of being exact, so it would not have garnered any extra notice either. An ancient Babylonian manuscript from this time period makes no mention of the conjunction being extra special in any way.
Chinese and Korean astrologers observed a comet in 5 BC, so perhaps it may have been a comet, although the astrologers of the day considered comets to be a bad omen (the harbingers of returning karma)?
Others have surmised that maybe some ancient star went supernova and exploded during this period, presenting observers on earth with a brilliant night sky for a period of time.
Maybe this is a Darshan question?