1. Astronomy 1010 Planetary Astronomy Fall_2014 Day-9

2. Course Announcements Smartworks Chapter 2: Fri. 9/19 Read Chapter 2, 3 Dark Night Observing – Tues. 9/16 & Wed. 9/24 – 7:30pm at the Observatory Exam-1 – Friday Sept. 19

4. Lecture – Tutorial Path of the Sun: pg 89 Work with a partner! Read the instructions and questions carefully. Discuss the concepts and your answers with each other. Come to a consensus answer you both agree on. If you get stuck or are not sure of your answer, ask another group. If you get really stuck or don’t understand what the Lecture Tutorial is asking, ask one of us for help.

5. Lecture – Tutorial Seasons: pg. 93 Work with a partner! Yada Yada Yada … This one is homework Also, look at the ones on: pg 11 – Solar vs. Sidereal Day Pg. 13 - Ecliptic

6. Stuff in Chapter 2 Coordinates Position Daily Motion (spin of Earth on its axis) Visibility of the sky Year Motion (Earth orbits the Sun) Seasons (tilt of the Earth’s axis) Precession of the equinoxes Motion and phases of the Moon Eclipses

7. Special Days of the Year  Summer solstice: Sun farthest north.  Autumnal equinox: Sun on the equator, moving southward.  Winter solstice: Sun farthest south.  Vernal equinox: Sun on the equator, moving northward.

8. Precession  Currently, the north celestial pole is near the bright star Polaris.  Earth’s axis wobbles with a period of 26,000 years.  Location of the poles slowly shifts.

9.  Earth wobbles like a top, slowly.  Since the axis shifts, the equator shifts.  Positions of the equinoxes precess as well.

11. The Moon’s Motions Because the orbit is elliptical and not circular, the rotation speed doesn’t always match the orbital speed.

12. The Month? Full Moon to Full Moon takes 29.53 days

14. The Cycle of Lunar Phases

15. The moon does rotate. The moon takes the same amount of time to complete one rotation as it does to complete one orbit

16. The orbital period is not the same as the cycle of phases Cycle of phases: The synodic month 29.53 days The Orbital Period is the Sidereal Month: 27.32 days

17. Lecture – Tutorial Cause of Moon Phases: pg 81 Work with a partner! Read the instructions and questions carefully. Discuss the concepts and your answers with one another. Come to a consensus answer you both agree on. If you get stuck or are not sure of your answer, ask another group. If you get really stuck or don’t understand what the Lecture Tutorial is asking, ask one of us for help.