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Sample Astronomy Exam
Answer the following Multiple Choice Questions by circling the correct response.
1) Imagine that you are visiting Antarctica on a cruise to see penguins. You step outside at night and look at
the stars. Where would you look to see the South Celestial Pole?
A) North, near the horizon (0 altitude)
B) Near the zenith (90altitude)
C) North, near 43 altitude
D) Northwest, in the direction towards the U.S.A.
E) The SCP cannot be seen from this location.
2) During Spring Break you and your friends plan to travel south to Cancun, Mexico for a week of sun and fun.
You arrive in Cancun on a clear night. You look up at the stars and notice that they appear different that the
stars you see in Syracuse, NY. Which of the statements below is true regarding the appearance of the stars
in Cancun? Circle all that are true.
A) Polaris will appear higher in the sky than as seen in Syracuse.
B) The circumpolar region will appear smaller compared to its size in Syracuse.
C) Stars will complete one cycle in the same time as seen in Syracuse.
D) You can see stars in the southern sky that are not visible from Syracuse.
3) The long exposure image of star trails shown
below was taken while looking toward the east.
From which of the locations listed below was the
image obtained?
A) Sydney, Australia (Latitude 34 S)
B) Lima, Peru (Latitude 12 S)
C) Quito, Equador (Latitude 0 N)
D) Canary Islands (Latitude 29 N)
E) Berlin, Germany (Latitude 52 N)
29°
EASTERN HORIZON
4) Which of the following locations is closest to the
north celestial pole?
A) RA = 14 h
dec = -85
B) RA = 0 h
dec = -43
C) RA = 23 h
dec = +43
D) RA = 14 h
E) RA = 8 h
dec = +85
dec = -2
5) Which of the following coordinates in your local horizon system (in Syracuse, NY at 43 N) is closest to the
zenith?
A) Az. = 180, Al. =43
D) Az. = 35,
Al. = 2
B) Az. = 273, Al. =52
E) Az. = 3,
Al. = 48
C) Az. = 90,
Al. = 90
Imagine that you are observing the stars at an observatory located outside El Paso, Texas (latitude = 32N).
You may find the diagram below helpful.
Zenith, +58° dec
Cel. Eq. +0° dec
NCP, +90° dec
32°
S
58°
58°
32° altitude
Southernmost visible
star , -58° dec
N
Circumpolar Boundary,
+58° dec
F) At what altitude would Polaris appear above the northern horizon?
Polaris would appear above the northern horizon at 32° altitude.
G) Would a star with a declination of +60 be circumpolar? Explain.
A star with a declination of +60 be circumpolar. It would dip to 2° above the northern horizon.
H) What would be altitude of the Celestial Equator looking south?
The altitude of the Celestial Equator looking south would be 58°.
I) Would you be able to observe stars as far south as -50 declination? Explain.
Since the southernmost visible star has a declination of -58°, then a star at -50° dec would be
visible reaching a maximum altitude of just 8° above the southern horizon.
J) Where would the celestial equator intersect the horizon?
The celestial equator intersects the horizon due East and due West for all observers.
Questions 6 and 7 below address the apparent motion of the stars as seen by an observer in El Paso, Texas. A
map of the United States below indicates the location of this city.
Syracuse, NY
El Paso, TX
6) If a particular star passed through the meridian in Syracuse, NY, how many hours before that same star
crossed the meridian in El Paso TX (see map at the beginning of the problem)?
A) 1 hr
C) 3 hr
E) 5 hr
D) 4 hr
B) 2 hr
Since there are 105°-76° = 29° longitude between Syracuse and El Paso and the stars
appear to mover around the Earth at a rate of 15°/hour, then the time between the star
29 degrees
 1.93 hr .
degrees
15
hour
7) In each of the boxes below, sketch carefully the apparent motion of the stars as seen in El Paso Texas
looking north, east and south. Include all quantitative information and timescales regarding the apparent
motions. Use the margins to record any notes regarding the apparent motions you think are relevant.
passing through the meridian in Syracuse and then in El Paso is
60
50
40
Altitude
30
20
10
Apparent Motion of the Stars Looking North





Polaris (NCP, really) is 32° altitude above the northern horizon.
Stars appear to revolve ccw around Polaris
Stars require 23h 56m 4.09s to complete one revolution around Polaris (The Sidereal Day)
The circumpolar boundary is (90°-32°) = 58° declination. All stars with declinations north of
58° declination are circumpolar. (Dashed Line)
Looking North from El Paso stars are above the horizon for more than 12 hours.



The Celestial Equator intersects
the horizon due East (and West).
The Celestial Equator and the
paths of rising stars rise on a
slant angle to the South of 32°.
Stars are above the horizon
looking East (or West) for about
12 hours.
Celestial Equator
32°
32°
32°
32°
Apparent Motion of the Stars Looking East




The SCP is 32° below the
southern horizon
Stars appear to revolve cw
around the SCP
Stars are above the horizon
looking South from El Paso for
less than 12 hours.
The southernmost visible star is
(-90°+32°) = -58° declination.
All stars with declinations south
of -58° declination are never
above the horizon as seen from
El Paso.
Southernmost visible
star at -58° dec
Apparent Motion of the Stars Looking South
Stars never rise
Answer the following six questions referring to the Whole Sky Map below.
All Sky Map
B
C
East
A
Celestial Equator
West
Ecliptic
D
12 Hr RA
6 Hr RA
0 Hr RA
18 Hr RA
12 Hr RA
9) What is the name of the point labeled C? Spring Equinox
10) When the Sun is at point B where will it rise along the local observer’s horizon? (Assume a northern
hemisphere observer.) Justify your answer using properties (rules) of the celestial sphere.
When the Sun is at point B it will act like a northern star and share all the properties of a northern star (e.g.
rise N of E, reach a high maximum altitude at transit, set N of W and be above the horizon for more than 12
hours). So the Sun will rise north of east.
11) At which of the labeled points A through D will the Sun be above the horizon for the shortest time for an
observer at Syracuse, NY?
Point D
12) What is the declination of the Sun at the point labeled D? -23½ °
13) At which of the labeled points will the Sun set to the south of west? Point D
The date is Dec 22. You observe that the Sun sets that day along the horizon as shown in figure below.
14) One week later will the Sun set at
A. the same location along the horizon,
B. to the right of the location shown above, or
C. to the left of the location shown above?
On Dec 22 the Sun is at its southernmost position
below the celestial equator. A week later it will
have move to the north a bit. So the Sun will set a
little more north – or to the right on the figure.
The image below illustrates the path of the Sun across the sky on three different days as seen from Syracuse,
NY.
A
B
East
C
South
West
15) Which of the paths labeled A, B or C, could represent the path of the Sun on Mar 22?
A) A
D) More information is needed to
answer the question
B) B
C) C
E) None of the above.
16) Which of the paths labeled A, B or C, could represent the path of the Sun the Winter Solstice?
A) A
D) More information is needed to answer the
B) B
question
E) None of the above.
C) C
17) Which of the paths labeled A, B or C, could represent a day with 9 hours of daylight?
A) A
D) More information is needed to answer
B) B
the question
E) None of the above.
C) C
18) The image to the right illustrates the shadow cast by a vertical pole
placed in the northern hemisphere of the Earth at noon on September
22. One week later, would the shadow cast by the pole be shorter, the
same length or longer? Explain in a few sentences.
On Sep 22 the Sun is on the Fall Equinox at 0° declination and is
heading south (point A on the All Sky Map above). Since the Sun is
heading south, it maximum altitude at transit (i.e. noon) will be lower
one week after Sep 22. If the Sun has a lower maximum altitude at
noon then its shadow will be longer. The Sun’s shadow will be longer
one week after Sep 22.
To the Sun
The image below shows the Sun at the meridian.
Sagittarius
E
S
W
19) What constellation did the Sun rise in on the day the image above was taken?
A. Virgo
D. Ophiuchus
E. Sagittarius
B. Libra
C. Scorpius
20) We have presented in the class the concept of the Sun as a moving star to
explain its apparent annual motion. Equivalently, the apparent annual motion
of the Sun could be explained by the real motion of the Earth. In a few
sentences explain why the solar day is a different length from the sidereal day
using the aspects of the real motion of the Earth. You may refer to the figure to
the right.
You must correctly define the sidereal day as the time required for the Earth to rotate once on its axis
relative to the stars (23h 56m 4,.09s) and the solar day as the average time between two adjacent noon’s (24
h). Then you must correct and articulately describe that these times are different due to the Earth’s
revolution around the Sun while it is rotating on its axis. Use the figure to illustrate you answer.
See section 3.6.2 Solar and Sidereal Time as Viewed from Space in AstronomyNotes for a thorough
discussion of this problem.
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Name__________________________
Solve the following problems showing your work.
21) The average distance between the stars in the disk of the Milky Way galaxy is about 3.26 light years. How
many Suns could fit side-by-side in the average distance between the stars in the disk of the Milky Way
galaxy?
The phrase “how many “in the question is the hint to use a ratio to solve the problem. The ratio you need is
 9.46  1012 km 

3.26 ly  
1 ly
Average Distance between Stars
3.26 ly

  2.22  107  22.2 Million


Diameter of the Sun
2  696,000 km
2  696,000 km
About 22 million Suns could fit side-by-side in the average distance between the stars in the disk of the
Milky Way galaxy
22) If the Earth were scaled down to the size of a golf ball (diameter = 4.27 cm), what would be the distance
from the Sun to Pluto (actual distance of 40 AU)?
This is a scale problem where proportions are best suited for solving the problem.
Model Size #1 Model Size #2

Actual Size #1 Actual Size #2
Let #1 be the the diameter of the Earth and #2 be the distance from the Sun to Pluto.
4.27 cm
x

2  6,378 km 40 AU
You must convert 40 AU into km before solving. 40 AU = 40∙150×106 km = 6×109 km.
4.27 cm
x

2  6,378 km 6  109 km
Now solve for x using cross-multiplication and isolating x.
4.27 cm  6 109 km
x
 2.01106 cm  2.01104 m  2.01101 km  20.1 km
2  6,378 km
If the Earth were scaled down to the size of a golf ball (diameter = 4.27 cm), the distance from the Sun to
Pluto (actual distance of 40 AU) would be about 20 km.
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23) If astronauts were to travel to the nearest star past the Sun, Proxima Centauri, using a spacecraft that
travelled at commercial airliner speeds (1,000 km/hour or 278 m/s), how much time would be required to
make the journey? The distance to Proxima Centauri is 4.3 ly. Express your answer in seconds and in
years.
d
problem where the distance d is 4.3 ly and the velocity v is 278 m/s. Before solving the
v
problem we need to convert the distance into meters so the length units in the velocity cancel the distance
units.
This is a t 
4.3 ly = 4.3∙9.46×1015 m = 4.07×1016 m
Now solve for time and convert from seconds to years. Note that to convert from seconds to years I use the
fact that 1 year = 3.15×107 seconds as listed on the formula sheet on the last page of the exam.
d 4.07  1016 m
1 yr



 1.46  1014 s  1.46  1014 s  
 4.64  106 yr  4.64 million yr
7 
m
v
 3.15  10 s 
278
s
If astronauts were to travel to the nearest star past the Sun, Proxima Centauri, using a spacecraft that
travelled at commercial airliner speeds (1,000 km/hour or 278 m/s), the time would be required to make the
journey would be 4.64 million years.
t
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Astronomy Formula and Constants Sheet for Exams
Conversions
Formulas
A
L

2D
360 
Main Sequence Lifetime t 
M
1010 yr
L
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