Now when Jesus was born in Bethlehem of Judaea in the days of Herod the king, behold, there came wise men from the east to Jerusalem, Saying, Where is he that is born King of the Jews? for we have seen his star in the east, and are come to worship him. Matthew 2: 1-2
What was this star the wise men followed? For centuries, there have been those who doubted its existence, but according to David Reneke, a writer and lecturer for Australasian Science Magazine, this famed star did indeed appear during the reign of Herod. Modern software programmes have enabled today’s astronomers to re-create what people would have seen in the night skies around the time most researchers agree Jesus’s birth took place (between 3 BC and 1 AD). A combination of these re-creations and historical records reveal that some unusual, and extremely rare, conjunctions (planetary grouping) were visible from 3 BC to 2 BC.
http://www.davidreneke.com/was-the-xmas-star-real/
The time of year in which they appeared (August 12th, 3 BC and June 17th, 2 BC) indicates that Jesus was NOT born during the season the event is now celebrated, but as has already been said in another post, the early Church sought to draw pagans to the Faith by tying it to the winter solstice. And when is much less important than why.
For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. John 3: 16
You may find this new book on the Star of Bethlehem useful https://www.facebook.com/SoBskepticbook