Astronomy 1010-H Planetary Astronomy Fall_2015 Day-10

Course Announcements SW chapter 2 – due Monday 9/21; 2pm How is the lunar observing going? How is the sunset/sunrise observing going? 1 st Quarter night – Mon. 9/21 -7:30pm – on campus Exam 1: Mon. Sept. 21 This Week: APSU-OUR: Research & Creative Activity Week. Events in the library 2:30-3:30 every day.APSU-OUR

Spacecraft Reports Chantal H. – New Horizons Ashley G. – Dawn Mahalia S. – NuStar Tristan C. – Mangalyaan Spencer B. – Voyager Arielle P. – Curiosity Rover Lars A. – Cassini Sarah E. – Rosetta John M. – Mars Phoenix Jordan T. – Galileo Rashun B. – Apollo Missions

The Cycle of Lunar Phases

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

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

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.

i_Clicker Question ClassAction: Questions: Lunar Cycles: Phase Evolution; option 1

Lecture – Tutorial Predicting Moon Phases: pg 85 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.

i_Clicker Question ClassAction: Questions: Lunar Cycles: Identify Lunar Position from Phase

i_Clicker Question ClassAction: Questions: Lunar Cycles: Phases Visible; option 1

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

Eclipses!

 Three types of solar eclipses: Total: The Moon completely blocks the Sun’s light. Partial: Only part is blocked. Annular: The Sun appears as a bright ring surrounding the Moon.

Solar Eclipses  Solar eclipses happen at new Moon.  Moon passes between Earth and the Sun.  Only a small portion of Earth can witness each one.

 The part of the Moon’s shadow you are in determines which type of solar eclipse you see.  Umbra: Total or annular.  Penumbra: Partial.

 Lunar eclipses happen at full Moon.  Earth is between the Sun and the Moon.  Visible over a wider area of Earth.  Last a lot longer than solar eclipses.

 Eclipses do not occur every month because the Moon’s orbit is tilted 5.2° with respect to Earth’s orbit around the Sun.  Intersection: line of nodes.

Lunar Eclipse: Earth passes directly between the Sun & Moon

The Total Lunar Eclipse Next one is April 15, 2014 for North America

A Solar Eclipse requires much more precise alignment

The Moon’s shadow is not large enough to cover the Earth

Partial eclipses are more common than total eclipses

Annular Eclipses occur when the Moon is at or near apogee

Solar Eclipses take hours to develop but last only minutes