Midrasch zu Jeschijahu 5:12

R. Simon b. Pazi in the name of R. Joshua b. Levi who spoke in the name of b. Kappara, said: "Concerning him who understands the science of astronomy and does not practice it, the passage says (Is. 5, 12.) But the deeds of the Lord, they regard not, and the work of His hands they behold not." R. Samuel b. Nachmeini in the name of R. Jonathan said: "Whence do we learn that a man is commanded to study the science of astronomy? It says (Deu. 4, 6.) Keep therefore and do them; for this is your wisdom and your understanding before the eyes of the nations. What kind of wisdom and understanding is recognized in the eyes of the nations? It is the wisdom of astronomy."