When did God bring Abraham out of Ur of the Chaldees?

Les explains that God brought Abraham out of Ur of the Chaldees at exactly the right time, on God's timetable. He notes God was never a day late or early, and Abraham was set toward Canaan to become the father of the Jewish race. Les also points out that exactly 430 years later was the Passover night in Egypt, when Moses was ready to lead Israel out of captivity. He further illustrates God's precise timing: there was a 40-year span from leaving Egypt until entering the Promised Land, which was 40 years to the day. On the Passover night in Egypt, it was the same day and month of the year, but 40 years later, when they celebrated the Passover with Joshua leading them across the Jordan River. Les cites Sir Robert Anderson's realization that from the decree to Nehemiah to rebuild Jerusalem, as recorded in Nehemiah 2, until the triumphal entry or Palm Sunday, was exactly 483 years as prophesied.