The first appearance of the star seems to mark the exact time of Jesus’ birth – at least King Herod interpreted it this way:
Matt 2:7 “Then Herod called the Magi secretly and found out from them the exact time the star had appeared.”
This implies that the Messiah – Jesus was born on the day the star appeared in the sky, and it appeared before Passover.
The comet of 5 BC recorded by the Chinese appeared sometime between the 9th March and 6th April in 5 BC in China. In 5 BC the Passover in Jerusalem was on the 20th April. People arrived for Passover a week before so they could do purification rites, and the feast itself lasted a week.
The Passover lambs – without spot or blemish – were chosen on the 10 Nisan of the Jewish calendar which was Sunday 14th to Monday 15th April 5 BC.
Colin Humphreys does not say this, but in my estimation, the latest date on which the star appeared was the 6th April – if Jesus was born on the 6th April and circumised eight days later, he would have been circumcised on the 14th April. Thus, he would have received the symbol of being born of the chosen people on the day that the sacrificial lambs were chosen.
Colin Humphreys notes that in the gospel of the Apostle John, John the Baptist twice says “Look, the Lamb of God” as Jesus came near (John 1:29; 1:36). This is strange phraseology, unless John the Baptist knew that Jesus was born at Passover. John the Baptist would have known when Jesus was born as they were related to each other through Mary and her aunt Elizabeth.
He also notes that Jews expected the Messiah to come in the month of Nisan of the Jewish calendar. This marks the season of the Exodus from Egypt and Passover.
I believe that Jesus was born just before the Passover lambs were chosen for the sacrifice of Passover. It means that both his birth and death were linked to his identity of being the ‘Lamb of God’.
Merry and True 