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Across 1. the assistant of tycho brahe, who continued brahe's work 6. a telescope that uses curved mirrors to gather and focus light 7. a section of the sky that contains a recognizable star pattern 11. the angle between an object in the sky and the horizon 12. another ancient site that is probably used to make observations of the sky, located near Salisbury, England 13. a measure of how far north or south an object is from the celestial equator 17. wrote a book that combined all the ancient knowledge of astronomy he could find 18. discovered Uranus in 1781 20. the study of all physical objects beyond earth 22. person who created the julian calendar 24. an instrument that collects electromagnetic radiation from the sky and concentrates it for better observation 25. first scientist to explain why celestial objects move as they do 26. this ancient civilization was the heart of the major empire located in present day Iraq 27. this theory states that the sun is the center of the universe 28. the first scientist to successfully use a telescope to observe the night sky

Down 2. a grouping of stones near this place is the earliest recording of astronomical observations 3. all the wavelengths of electromagnetic radiation 4. a danish astronomer who used several tools to observe the sky 5. a telescope that uses a set of lenses to gather and focus light 6. a measure of how far east an object is from the point at which the sun appears on the first day of spring 8. this scientist successfully explained the phases of the moon and the eclipses 9. roughly the amount of time required for the moon to orbit the Earth once 10. a unit of length equal to the distance that light travels through space in 1 year 13. the time required for the Earth to rotate once on it's axis 14. the time required for the Earth to orbit the sun once 15. a system for organizing time 16. our modern calendar was developed from this 19. this theory stated that the Earth is the center of the universe 21. the apparent path the sun takes across the celestial sphere each year 23. a year in which an extra day is added to the calendar