Across
- 4. Developed a geocentric model of the universe, suggested rotation of Earth cause of rotation of heavens
- 10. Motion of a planet opposite to that of other bodies
- 11. First to predict solar eclipse (according to Herodotus)
- 13. Father of modern observational astronomy
- 14. Reaffirmed the heliocentric model of the solar system
- 15. Known for discovering the elliptical orbits of the planets
- 16. Belief that the sun is the centre of the universe
- 19. Used epicycles to explain retrograde motion of the planets
- 20. Groups stars together to make them more easily identifiable
Down
- 1. Calculated the circumference of the earth to 95% accuracy
- 2. First written catalogue categorizing motions of stars and planets, written by Ptolemy
- 3. One of the last naked eye astronomers, observed a supernova
- 5. The "wobbling" of an object (like Earth) on its axis
- 6. The path of the sun in the sky during the year
- 7. Believed that the universe was composed of 4 elements
- 8. Known for formulating laws of motion and universal gravitation
- 9. First to develop the heliocentric model
- 12. Discovered galaxies beyond the Milky Way in 1919
- 17. The "forgotten constellation", the 13th constellation on the ecliptic
- 18. Belief that the Earth is the centre of the universe