1. Earth and Sky Geometries of the Sky

2. Latitude and Longitude

3. Grid system to find things on Earth Grid system to find things on Earth Poles, Prime Meridian, Equator Poles, Prime Meridian, Equator

4. Celestial Sphere Like Lat and Long for space Like Lat and Long for space Extrude Poles and equator Extrude Poles and equator Ecliptic Ecliptic

5. Ecliptic Tilt of the Earth ~23.5 o Tilt of the Earth ~23.5 o Why the ecliptic isn’t the celestial equator Why the ecliptic isn’t the celestial equator

6. In the Sky… Where to look for planets Where to look for planets

7. Polaris, the North Star Always there Always there –Not exactly stationary Great for navigation Great for navigation

8. RA and Dec

9. Seasons Ecliptic determines when each season starts Ecliptic determines when each season starts

11. Why a Year Has 365.24 days Sidereal-Solar Sidereal-Solar Extra 1 o to turn Extra 1 o to turn 361/360*24hrs=0.0 67 extra hours 361/360*24hrs=0.0 67 extra hours Or 4 min/day Or 4 min/day Held over for leap year Held over for leap year To keep Sun in the correct part of the sky To keep Sun in the correct part of the sky

12. Moon Phases Sunlight comes from this direction Depicts fraction of Moon visible

13. Lunar Eclipse Safe to view Safe to view Full Moon phase Full Moon phase Moon at perigee for the longest duration Moon at perigee for the longest duration Used by Aristarchus to get relative size of Earth and Moon Used by Aristarchus to get relative size of Earth and Moon

15. Solar Eclipse NOT SAFE to view directly NOT SAFE to view directly Aphelion, perigee, node Aphelion, perigee, node

17. Other Kinds of Eclipses Partial Partial Annular Annular

18. Annular Eclipse May 20, 2012