Astronomy 1010-HFall_2015

Day-6Planetary Astronomy

Course Announcements• 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?• Next week: • Dark Night Observing on Tues. 9/8 & Thur. 9/10

• Sat. 9-5: Football vs Mercer, 4pm; Tailgate at 1pm

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.

Spacecraft Reports• Chantal – New Horizons• Ashley G. - Dawn

Use Winter Triangle to find constellations during evenings

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

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

Celestial Sphere

Celestial Sphere Rotation

Celestial Sphere Rotation

Celestial Sphere

Star A

Star B

1

1

3

2

2

4

4

3

Figure 2

Horizon

Is the horizon shown a real physical horizon, or an imaginary plane that extends from the observer and Earth out to the stars?Can the observer shown see an object located below the horizon?Is there a star that is in an unobservable position?When a star travels from being below the observer’s horizon to being above the observer’s horizon, is that star rising or setting?

Tutorial: Position – p.1Work with a partnerRead the instructions and questions carefullyDiscuss your answers with each otherCome to a consensus answer you both agree

onIf you get stuck or are not sure of your

answer ask another groupIf you get really stuck or don’t understand

what the Lecture Tutorial is asking as one of us for help

In what direction is the observer facing?

A) toward the South

B) toward the North

C) toward the East D) toward the

West

Celestial Sphere

Celestial Sphere Rotation

Celestial Sphere Rotation

Celestial Sphere

Star A

Star B

1

1

3

2

2

4

4

3 Horizon

Concept Quiz

Where would the observer look to see the star indicated by the arrow?

A. High in the NortheastB. High in the SoutheastC. High in the Northwest D. High in the Southwest

Celestial Sphere

Celestial Sphere Rotation

Celestial Sphere

Star A

Star B

1

1

3

2

2

4

4

3 Horizon