Complex sentence: A professor and chair of the astronomy department at Boston University in the United States, in 1965 he published an analysis of Stonehenge in which he was the first to propose its purpose as an ancient astronomical observatory used to predict movements of sun and stars.
Split into simpler sentences: A professor and chair of the astronomy department at Boston University in the United States. In 1965 he published an analysis of Stonehenge in which he was the first to propose its purpose as an ancient astronomical observatory used to predict movements of sun and stars.