Download Define the following terms in the space provided

SCI-103 Introductory Astronomy Quiz #1 Spring 2014
Name_____________________
Class Meeting Time_____________
Answer the following Multiple Choice Questions by circling the correct response.
1) 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.
2) 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)
EASTERN HORIZON
3) 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
The date is Dec 22. You observe that the Sun sets that day along the horizon as shown in figure below.
4) 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?
5) 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.
6)
Zenith, 32 dec
Cel. Eq., 0 dec
Circumpolar
Region
NCP, 90 dec
32
58
58
32
S
N
Southernmost Visible Star, -58dec
Circumpolar Boundary, 58dec
A) Would a star with a declination of +60 be circumpolar? Explain.
Yes, a star at +60 declination is 2 within the circumpolar boiundary.
B) What would be altitude of the Celestial Equator looking south?
The altitude of the Celestial Equator is 58.
C) Where would the celestial equator intersect the horizon?
The Celestial Equator intersects the horizon exactly due east and due west for ALL observers.
7) If a particular star passed through the meridian in Syracuse, NY (43N, 76W), how many hours before that
same star crossed the meridian in Tokyo, Japan (36N, 130E)?
A) 1 hr
C) 3 hr
E) 5 hr
B) 2 hr
D) 4 hr
The star first crossed the meridian in Tokyo at 130 E longitude and then, as the Earth rotated at 15 per hour,
crossed the meridian in Syracuse at 76 W longitude. The difference in longitude between those two locations
is 130+76 = 206. So the time between the star transiting the meridian at each location is
206
 13.7 hours
15 per hour
Unfortunately the instructor neglected to change the multiple choice responses after he changed the question.
So this question was not counted on the quiz, but could appear in a similar form on the exam.
Question 7 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
8) 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.
Circumpolar Boundary
at 58 dec.
Location: 32 N latitude as
determined from the map above
60
Place Polaris (NCP, really) due North
at an altitude of 32.
50
Draw the path of stars circling Polaris
counter-clockwise.
40
Identify the circumpolar region and
its boundary at 58 declination.
Altitude
30
State the time it takes for the stars to
complete one cycle 23h 56m 4.09 s –
the sidereal day.
State that when looking north the
stars are above the horizon for more
than 12 hours.
32 Altitude
20
10
Apparent Motion of the Stars Looking North
Answer the following six questions referring to the Whole Sky Map below.
All Sky Map
B
C
East
Celestial Equator
A
West
Ecliptic
D
12 Hr RA
6 Hr RA
0 Hr RA
8) What is the name of the point labeled C?
18 Hr RA
12 Hr RA
Spring Equinox
9) At which of the labeled points A through D will the Sun be above the horizon for the longest time for an
observer at Syracuse, NY?
B
10) What is the declination of the Sun at the point labeled D?
-23½
11) At which of the labeled points will the Sun set to the south of west?
D
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
12) 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.
13) 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.
To the Sun
On September 22 the Sun is crossing the celestial equator and heading
south (the descending node it is sometimes called), Since the Sun will
be a\t a more southerly declination in a week after the 22, it will also
have a lower maximum altitude at transit. The lower altitude will
cause the shadow of the stick to appear longer. So the shadow of the
stick will appear longer as the Sun moves farther south.
The image below shows the Sun at the meridian.
Sagittarius
E
S
W
14) What constellation did the Sun rise in on the day the image above was taken?
A. Virgo
C. Scorpius
E. Sagittarius
D. Ophiuchus
B. Libra
“On a diurnal timescale the Sun appears to move with the stars as if attached to the Celestial Sphere”
Solve the following problems showing your work.
15) 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?
Use a ratio to solve this problem
 9.46  1012 km 

3.2 ly  
12
1
ly
3.2 ly

  3.2  9.46  10 km  2.22  107  22.2  106  22.2 Million

2  R Sun
2  696,000 km
2  696,000 km
You could fit 22.2 Million Suns between the Sun and the nearest star.
5
Astronomical Constants
Quantity
Value
astronomical unit (A.U.) 149,597,870.691 kilometers
light year (ly)
9.460536207× 1012 km = 63,240 A.U.
parsec (pc)
3.08567802× 1013 km = 206,265 A.U.
sidereal year
365.2564 days
tropical year
365.2422 days
Gregorian year
365.2425 days
Earth mass
5.9736× 1024 kilograms
Sun mass
1.9891× 1030 kg = 332,980 × Earth
mean Earth radius
6371 kilometers
Sun radius
6.96265 × 105 km = 109 × Earth
Sun luminosity
3.827× 1026 watts
16) 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.
This question was inadvertently left on the quiz. You did not have to answer it. I’ll provide the solution
because a question like it could appear on the exam.
Use the relationship t 
d
to solve this problem.
v
 9.46  1015 m 

4.3 ly  
15
1 ly
d 4.3 ly

  4.3  9.46  10 m  1.46  1014 s  4.63  106 y  4.63 Million years
t 

m
m
v 278 m
278
278
s
s
s
The journey would take 4.63 million years – as long a time as the human species has walked the Earth.
6
Astronomy Formula and Constants Sheet for Exams
Conversions
Formulas
A
L

2D
360 
Main Sequence Lifetime t 
M
1010 yr
L
7