Sept 11, 3 BC. It was the Day of Trumpets.
As I recall, somewhere around 6:30 am.
The Magi's followed Jupiter in its helical rising. They noticed the series of planetary conjunctions, like the one this last weekend, that foretold the coming of the new King.
And I believe that they were following the teachings of Daniel when he was in captivity and rose to a prominent position among the 'wise men' due to his ability to listen to God and interpret dreams.
Seems that God used Daniel and the magi to help preserve the Christ from being nurdered as a young child at the hands of Herod.
You're right. Feast of Trumpets. History books that I have say that Herod died April 1, 4 BC. That would put His birth more than likely the Feast of Trumpets 5 BC, thus being about 30 years old in 26 AD in the 15th year of the reign of Tiberius Caesar. [Luke 3:1].