Astronomy 1010 Planetary Astronomy Fall_2015 Day-11

Course Announcements SW chapter -2 due: Mon. 9/21; 2pm How is the lunar 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

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

During a total eclipse the Sun’s corona is visible

i_Clicker Question ClassAction: Questions: Phase2, Eclipse2, Tides; option 1

Predicting Eclipses The Saros Cycle…18 years 11.3 days

Exam-1 to here

What Would You See on Mars?

Projected Eclipse Times Eclipse Path Point of Greatest Eclipse Lat.: ° N Long.: ° W Total Solar Eclipse Duration of Totality: 2m40.1s APSU Observatory Lat.: ° N Long.: ° W Total Solar Eclipse Duration of Totality: 2m23.4s

Projected Eclipse Times APSU Observatory Lat.: ° N Long.: ° W Total Solar Eclipse Duration of Totality: 2m23.4s Magnitude: Event Date Time (UT) Alt Azi (C1) : 2017/08/2116:56: ° 149.7° (C2) : 2017/08/2118:25: ° 198.9° Max : 2017/08/2118:26: ° 199.5° (C3) : 2017/08/2118:27: ° 200.2° (C4) : 2017/08/2119:52: ° 235.2°

Projected Eclipse Weather

Clarksville, TN

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