What do you think? Do the stars stay in the same position in the sky all day/night long? Do we see the same stars all year round every night?

What do you think?

• Do the stars stay in the same position in the sky all day/night long?

• Do we see the same stars all year round every night?

What do you think?

• What causes the stars move?

• Do the stars actually move in the way they appear from Earth?

• Is the daily motion of the Sun different from the stars?

Astrology: The belief that the positions of the stars and planets

as seen from Earth impact human events.

Constellations – the 88 semi-rectangular regions that make up the sky

• Northern constellations have Latinized Greek-mythology names:– Orion, Cygnus, Leo, Ursa Major, Canis Major, Canis

Minor

• Southern constellations have Latin names:– Telescopium, Sextans, Pyxsis

Use the Summer Triangle to find constellations during summer evenings

Use the winter triangle to find constellations during winter

evenings

Anyone recognize any shapes here?

Star Names

SIRIUS

Betelgeuse

Aldebaran

Rigel

Using Orion in to find other objects

Sirius

Aldebaran

Pleiades

Great Orion Nebula

Pleiades

SevenSisters

Subaru

Use the Big

Dipper in the

northern sky as a way to

find other groups of

stars

Consider the dome of the sky over our heads….

mixing bowl

inverted mixing bowl ….

Consider the dome of the sky over our heads….

Imagining a spinning Celestial Sphere

surrounding Earth aids in

thinking about the position

and motion of the sky

Imagining a spinning Celestial Sphere surrounding Earth aids in thinking about the position and motion of the sky

Animation!

Celestial Sphere Rotation


North Star

Star A

Star B

1

1

3

3

2

2

4

4

Earth’s Equator

Figure 1

Celestial Sphere



Celestial Sphere

Star A

Star B

1

1

3

2

2

4

4

3

Figure 2

Horizon

Celestial Sphere



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.1• Work with a partner• Read the instructions and questions carefully• Talk to each other and discuss your answers with each

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 as one of us for help



North Star

Star A

Star B

1

1

3

3

2

2

4

4

Earth’s Equator

Figure 1

Celestial Sphere



Celestial Sphere

Star A

Star B

1

1

3

2

2

4

4

3

Figure 2

Horizon

North Star

Did you get the Key Ideas from the Position Lecture Tutorial?

In what direction is the

observer facing?

1. toward the South2. toward the North3. toward the East4. toward the West

Celestial Sphere



Celestial Sphere

Star A

Star B

1

1

3

2

2

4

4

3

Figure 2

Horizon

Imagine that from your current location you observe a star rising directly in the east.

When this star reaches its highest position above the horizon, where will it be?

A. high in the northern skyB. high in the southern skyC. high in the western skyD. directly overhead

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

Star A

Star B

1

1

3

2

2

4

4

3

Figure 2

Horizon

How long did it take to get this

picture?

Take out a piece of paper and put your name and student ID # on it along

with your answer!!

Earth’s rotation

causes the Sun, Planets,

Moon and stars to appear to move when viewed from

Earth

Nightly Motion of the Stars

• Imagine looking toward the East as a star rises above your horizon - what does it do after that?


Celestial Sphere



Celestial Sphere

Star A

Star B

1

1

3

2

2

4

4

3

Figure 2

Horizon


• For stars (the Moon and planets) that appear in the southern sky: Stars first rise near the eastern horizon, move upward and toward the south, and then move down and set near the western horizon.

What direction is the observer facing in this

picture?


• Imagine looking toward the North. What do stars appear to do over the course of an evening?


Celestial Sphere



Celestial Sphere

Star A

Star B

1

1

3

2

2

4

4

3

Figure 2

Horizon


• Looking North: Stars appear to move counter-clockwise around the stationary North Star (Polaris) – we call these circumpolar stars.

Looking North: Circumpolar Stars

– Circumpolar stars seem to move counter-clockwise around the stationary North Star.

– These constellations and stars are visible any night of the year in the NORTHERN sky because they never rise or set!

– Examples: Ursa Major, Ursa Minor, Draco, Cepheus, and Cassiopeia

What happens over time in the Northern Sky?

Tutorial: Motion – p. 3

• 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.

Your Birth SignROUGHLY, it is the constellation that the Sun is covering up during the day you are

born if you were born 2000 years ago.

Zodiac - The 13 Zodiacal constellations that our Sun covers-up (blocks) in the course of

one year (used to be only 12)

• Aquarius

• Pisces

• Aries

• Taurus

• Gemini

• Cancer

• Leo• Libra• Virgo• Scorpius• Ophiuchus• Sagittarius• Capricornus

The Zodiacal Constellations that our Sun covers-up

(blocks) in the course of one

year (only 12 are shown here)

North Star

365 days

1 dayAries

Pisces

Taurus

Gemini

Cancer LeoVirgo

Libra

Scorpius

Sagittarius

Capricornus

Aquarius

Figure 1

The Zodiacal Constellations that our Sun covers-up

(blocks) in the course of one year

(only 12 are shown here)

Which constellation would that be for the

situation shown?Pisces

Aries

Taurus

Gemini

Cancer

Figure 2 – What it would look like if you were the observer in Figure 1

South

North Star

365 days

1 day

Aries

Pisces

Taurus

Gemini

Cancer LeoVirgo

Libra

Scorpius

Sagittarius

Capricornus

Aquarius

Figure 1

Pisces

Aries

Taurus

Gemini

Cancer


South

North Star

365 days

1 day

Aries

Pisces

Taurus

Gemini

Cancer LeoVirgo

Libra

Scorpius

Sagittarius

Capricornus

Aquarius

Figure 1

E W

W

E

What time is it for the observer?

What is the name of the constellation that would appear on the observers

Eastern Horizon? Western?

For more practice at this – Try Part I of the “Seasonal Stars” Lecture Tutorial

Pisces

Aries

Taurus

Gemini

Cancer


South

North Star

365 days

1 day

Aries

Pisces

Taurus

Gemini

Cancer LeoVirgo

Libra

Scorpius

Sagittarius

Capricornus

Aquarius

Figure 1

E W

W

E

12 hours later what object will be at the position that Taurus is in

now?18 hours later where will the

Sun be? Where will

Scorpius be?For more practice at this – Try Part I of the “Seasonal Stars” Lecture Tutorial

Pisces

Aries

Taurus

Gemini

Cancer


South

North Star

365 days

1 day

Aries

Pisces

Taurus

Gemini

Cancer LeoVirgo

Libra

Scorpius

Sagittarius

Capricornus

Aquarius

Figure 1

E W

W

E

Two months from the time shown

what constellation will be high in the Southern sky, at

Midnight? At Noon?

What sign will a person be if they are born at that

time?For more practice at this – Try Part I of the “Seasonal Stars” Lecture Tutorial

Documents

What do you think? Do the stars stay in the same position in the sky all day/night long? Do we see the same stars all year round every night?