Even December 25 was chosen centuries after the event, evidence pointing to a spring or fall date for Christmas. But historical and biblical detective work narrows the window. The birth must have occurred between 8 B.C. when Augustus Caesar's census required Joseph to return to Bethlehem and either 4 or 2 B.C. when Herod died. In January of the next year they regroup with Mars joining them. We will witness that rare proximity of those three planets again in the year 2000.
Chinese astronomers record a comet.
Supernovas are stars that suddenly flare up, emitting hundreds of times as much light for a few months. In 1573 Tycho Brahe witnessed one so bright that it was visible in daytime. Other possibilities include meteors, fireballs, ball lightning or even zodiacal light. Different authors have supported one or another of these candidates. The faithful require none of these computations.