1. Physics 202: Introduction to Astronomy – Lecture 2 Carsten Denker Physics Department Center for Solar–Terrestrial Research

2. January 20, 2006Center for Solar-Terrestrial Research Prologue  Constellations  Celestial sphere  North and south celestial poles  Celestial equator  Celestial coordinates  Declination and right ascension  Solar and sidereal day  Ecliptic  Zodiac  Seasons  Summer and winter solstice  Vernal and autumnal equinox  Tropical and sidereal year  Precession

3. January 20, 2006Center for Solar-Terrestrial Research Constellations in the Sky

4. January 20, 2006Center for Solar-Terrestrial Research Celestial Coordinates

5. January 20, 2006Center for Solar-Terrestrial Research Solar and Sidereal Day

6. January 20, 2006Center for Solar-Terrestrial Research Long-Term Changes ‒ Precession

7. January 20, 2006Center for Solar-Terrestrial Research Group Problem  How and why does a day measured by the Sun differ from a day measured by the stars?  Assume that the Earth would orbit the Sun in the opposite direction. How would that affect the solar and sidereal day?

8. January 20, 2006Center for Solar-Terrestrial Research The Orbit of the Moon  Phases  New, quarter, and full Moon  Sidereal month (27.3 days) and synodic month (29.5 days)  Solar and lunar eclipses  Total, annular and partial solar eclipse  Umbra and penumbra

9. January 20, 2006Center for Solar-Terrestrial Research Lunar Phases

10. January 20, 2006Center for Solar-Terrestrial Research Lunar Eclipse

11. January 20, 2006Center for Solar-Terrestrial Research Solar Eclipse

12. January 20, 2006Center for Solar-Terrestrial Research Group Problem  Why aren’t there lunar and solar eclipses every month