Possible Clues:

• Ancient astronomer
• Ancient Greek astronomer
• Astro-theorist plots sequence from spaceship to LEM, yes?
• Greek astronomer
• Greek mathematician, astronomer and geographer of second century AD
• Alexandrian astronomer
• Influential second-century astronomer
• Copernicus proved him wrong
• Before 'heavy' singer loses central mass, turn over astronomer
• European claiming Egypt's last disembowelled mummy is Cleopatra's daddy