1. Apparent Celestial Movements

2. What are Celestial objects? • The things seen in our sky that are outside of the Earth’s atmosphere. • Sun • Moon • Stars • Planets

3. What is a Celestial Sphere? • The dome of night sky above your location extending from strait up to the horizon 360 degrees around. • We can use this to determine locations of celestial objects

5. How do we measure celestial object locations? • Using the: • Zenith • Azimuth • Altitude

6. Zenith • The point directly overhead, 90 degrees from the horizon.

7. Azimuth • Uses compass directions • Expressed as an angle measured from North (being 0 degrees), clockwise to East (90 degrees), clockwise to South (180 degrees), to west (270 degrees), and around the horizon back to 360 degrees.

8. Altitude • The angle above the horizon from 0 to 90 degrees.

9. The Sun in the celestial sphere • Day and night • Solar noon • Sun’s path with the changing seasons • Location- Latitude, Longitude

10. Day and Night • The Earth rotates on it’s axis causing day and night. • 24 hours = 1 rotation of Earth on it’s axis • As the Earth rotates it goes in and out of sunlight once per rotation

11. Why do we experience different amounts of daylight through the year? • The 23 ½ degree tilt of the earth’s axis: • Summer solstice (June 20)- Northern hemisphere tilted toward the sun will have more then 12 hours of daylight. • Winter solstice (December 20)- Northern hemisphere tilted away from the sun will have less then 12 hours of daylight • The equinoxes (March 23 and Sept. 23)- 12 hours of daylight, 12 hours of darkness.

12. Evidence supporting rotation • The Coriolis Effect (wind deflection) • Movement of a pendulum • Satellite images http://www.classzone.com/books/earth_science/terc/content/visualizations/es0403/es0403page01.cfm?chapter_no=visualization

13. What is Solar Noon? • Sun’s highest point in the observers sky • Found by finding the mid point between sunrise and sunset

14. Sun’s path with the changing seasons

15. Summer Solstice • Sun rises in ENE • Sun sets in WNW

16. Equinox’s • Rises in the East • Sets in the West

17. Winter Solstice • Rises ESE • Sets WSW

18. Changes with Longitude • Earth rotates counterclockwise 15 degrees per hour • 15 degrees /360 degrees = 24 time zones • Move 1 hour from zone to zone.

20. Changes with Latitude • Equator – 12 hours of daylight everyday • Mid and upper latitudes depend on the season http://www.daylightmap.com/?hl