Across
- 2. calendar that started in 622AD
- 4. telescope created by Newton
- 6. telephone engineer
- 8. most important instrument used by astronomers
- 11. small lens of a refracting telescope
- 12. coordinated universal time
- 14. a day that is one rotation of the earth relative to the stars
- 17. dark lines where color is absorbed
- 18. kalendae
- 20. comes from an ancient word that means moon
- 21. the most basic unit of time
Down
- 1. spectrum produced by a spectroscope
- 3. 24 hour time keeping
- 5. object on a celestial sphere crosses an observers meridian
- 7. computer controlled mirrors
- 9. large lens of a refracting telescope
- 10. based on the amount of time the earth was created
- 13. calendar named for Pope Gregory
- 15. level of detail
- 16. Januarius
- 19. equal night