Astronomy 1010-H
Planetary Astronomy
Fall_2015
Day-6

Course Announcements
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Smartworks Chapter 1: Due TODAY!
Grades will be downloaded on Saturday.
No class Monday (Labor Day)
Read Chapter 2.2, 2.3, 2.4
How is the lunar observing going?
How is the sunset/sunrise observing going?
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Next week:
Dark Night Observing on Tues. 9/8 & Thur. 9/10
• Sat. 9-5: Football vs Mercer, 4pm; Tailgate at 1pm

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Definitions & Terms -1
Circumpolar Star: A star which stays above the horizon at all times at the observers location.
Zenith: The point directly overhead, 90° from all horizons
(assuming they are flat). It does NOT have an azimuth associated with it.
Nadir: The point directly under your feet, opposite the zenith
Altitude: A measure of the height of an object from the ground up. It is measured perpendicular to the horizon. The horizon is 0° altitude. The Zenith is 90° altitude.
Azimuth: The point along the horizon –measured eastward from the north point- where you measure the altitude. Runs for 0° in the North, to 90° due East, 180° South; 270° West.

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Spacecraft Reports
Chantal – New Horizons
Ashley G. - Dawn

Use the Big Dipper in the northern sky as a way to find other groups of stars

Use Summer Triangle to find constellations during evenings

Use Winter Triangle to find constellations during evenings

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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

Coordinates

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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

Position
Is the horizon shown a real physical horizon, or an imaginary plane that extends from the observer and Earth out to the stars?
Celestial Sphere Rotation
Can the observer shown see an Celestial Sphere object located below the horizon?
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Is there a star that is in an unobservable position?
4 When a star travels from being below the observer’s horizon to being above the observer’s horizon, is that star rising or setting?
Figure 2
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Star B
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Celestial Sphere
Rotation
Star A
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Celestial Sphere
Horizon

 Work with a partner
 Read the instructions and questions carefully
 Discuss 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 as one of us for help

Concept Quiz
 In what direction is the observer facing?
Celestial Sphere Rotation
Star B
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 A) toward the South
 B) toward the North
 C) toward the East
 D) toward the West
Celestial Sphere
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Star A
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Celestial Sphere
Horizon
Celestial Sphere
Rotation

 Where would the observer look to see the star indicated by the arrow?
Celestial Sphere
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B.
C.
D.
High in the Northeast
High in the Southeast
High in the Northwest
High in the Southwest
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Star B
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Celestial Sphere
Rotation
Star A
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Celestial Sphere
Horizon