AST 101 Chapter 2

What is the rate of the Sun's diurnal motion across the sky?

15 degrees per hour

From horizon to opposite horizon, the sky takes up how much angular distance? a. 90 degrees Correct Response b. 180 degrees c. 360 degrees d. 100 degrees e. you can't fool me, this number varies with latitude

180 degrees

An observer notices that the Sun is directly overhead at midday during the Summer Solstice. What is this observer's latitude upon the Earth?

23.5 degrees North

The Sun, Moon, planets and stars rise in the ____ and set in the ____.

East, West

What happens to the position of Polaris in your sky as time advances over a period of a year?

It revolves in a very small circle around the north celestial pole.

What is the orientation of the Big Dipper asterism in winter?

It sits with its handle downwards

Where would the celestial equator appear to be located for an observer standing directly on one of the Earth's poles? Hint: Change your location on the Earth to the North Pole under Location in the Settings view.

It would be parallel to and coincident with the horizon

On what date does the Sun reach the most northerly point (the summer solstice) along the ecliptic? On what date does the Sun reach the most southerly point (the winter solstice) along the ecliptic?

June 21, December 21

On what date of the year does the Vernal Equinox occur? On what date of the year does the Autumnal Equinox occur? [Hint: Run time forward to find the two dates when the Sun is on the celestial equator.]

March 20, September 22

An observer in Earth's northern hemisphere is looking directly towards Polaris. In what direction is this observer facing?

North

The relatively bright star near the north celestial pole is:

Polaris

The star that is currently closest to the North Celestial Pole is: a. Arcturus b. Betelgeuse Correct Response c. Polaris d. Rigel e. Nicole Kidman Submit Your Answer

Polaris

Which of the following relatively bright stars is the nearest to the south celestial pole (SCP), as shown in the Sky Chart? (Hint: Use the Search facility to locate these stars and zoom in towards the SCP. Then use the Measurement Tool to measure their angular distance from the SCP.)

Polaris Australis (Sigma Octantis)

Why do we observe diurnal motion from the surface of the Earth?

The Earth rotates on its spin axis carrying an observer in a complete rotation from west to east once every 24 hours.

What is the relationship between the altitude of Polaris and the latitude of the observer?

The altitude of Polaris is almost the same as the latitude of the observer

How does the altitude of the north celestial pole relate to the observer's geographic latitude on the surface of the Earth?

The altitude of the NCP is equal to the observer's geographic latitude

Consider both of your sunrise observations. What appears to be the relationship between the angle that the track of the rising Sun makes with the horizon and the latitude of the observer?

The lower the latitude, the greater the angle that the track of the rising Sun makes with the horizon.

Which of the following constellations does the celestial equator not pass through?

Ursa Major

Polaris is part of which constellation?

Ursa Minor

A graduate student in geology who grew up in Florida (near the southernmost tip of the United States) gets to accompany her research professor to the North Pole. What will be different at the North Pole from the way she remembers the sky in Florida?

all of the above would be different from the way it is in Florida

Within a constellation, a smaller, recognizable pattern of stars is often called:

an asterism

As seen from the continental United States, the Big and Little Dipper a. are below the horizon throughout the year b. are at the zenith throughout the year c. are on the celestial equator throughout the year Correct Response d. are in the north circumpolar zone throughout the year e. none of the above

are in the north circumpolar zone throughout the year

From a city in the U.S., where in the sky would you look to see a star that is not turning with the motion of the sky in the course of a night?

at the north celestial pole

Where on Earth do stars always circle the zenith (and never rise and set)?

at the north pole

On the celestial sphere, halfway between the celestial poles lies the

celestial equator

The 88 sectors into which astronomers today divide the celestial sphere (the whole sky) are called

constellations

The Sun's apparent path around the celestial sphere is called a. the horizon b. the circumpolar zone c. the celestial equator d. the celestial hot-zone Correct Response e. the ecliptic

the ecliptic

The celestial sphere turns once around each day because

the planet on which we live is rotating

Someone who observes the sky every clear night in Boston for many years will NEVER get to see

the south circumpolar zone

The ecliptic is inclined at 23.5 degrees to the celestial equator. This is the result of:

the tilt of Earth's rotational axis with respect to the orbital plane of the Earth

Let's say we find a star that is located on the points or circles in the sky listed in the answer choices below. Then, on the same night, we move to a location on Earth that is some significant distance from our first location. There will now be a different star at or on:

the zenith

The strip of the sky through which the Sun, the Moon, and the bright planets appear to move in the course of a year is called:

the zodiac

The point in the sky directly above your head at any given time is called the

zenith

In the Northern Hemisphere, the altitude (height in degrees above the horizon) of the North Star is always roughly equal to the

latitude of the observer

Some Canadian troops are sent (as part of a U.N. peacekeeping force) to a country located on the Earth's equator. At night, when homesickness makes them gaze sleeplessly at the stars, which of the following will be familiar to them (the same at the equator as in Canada)

none of the above are the same on the equator as in Canada

The south celestial pole and the north celestial pole lie in the sky directly above

the Earth's axis

If the Earth goes around the Sun, why is the ecliptic not lined up with the celestial equator?

the Earth's axis is tilted by about 23 degrees from the vertical

Every celestial object appears to go around the Earth once a day. In addition to this motion, which celestial object has the fastest apparent motion in the sky?

the Moon