Download quiz 1 Spring 1995

Phys 102 Astronomy
Key
Name _____________________
Exam 1
OBSERVING THE SKY: Group Section
1)20 Complete the table.
BAYER
DES.
RA
2)10 Label the diagram with star names
and constellation lines for the stars
listed by the Atlas Charts.
α Boö
14h16m
-0.04
-0.6
37
Arcturus
β Boö
15h02m
3.50
-0.7
219
Nekkar
η Boö
13 55
2.68
2.4
37
Muphrid
3)2 Which of these stars is brightest in
our sky?
Arcturus, α Boö
α CrB
15h35m
2.2
0.3
75
Alphekka
3.1
-3.5
1369
Ras Algethi
4)2 Which of these stars would be
brightest if they were all at the same
distance? Ras Algethi, α Her
5)2 Which of these stars is farthest
Ras Algethi, α Her
from us?
VISUAL
MAG.
h
h
m
m
α Her
17 15
β Her
16h30m
(V)
ABSOLUTE
MAG.
(MV)
DIST.
(ly)
2.77
-0.5
148
Kornephoros
ζ Her
h
m
16 41
2.81
2.5
35
Zeta Her
β Dra
h
17 30
m
2.79
-2.9
361
Restaban
γ Dra
h
m
2.23
-1.1
148
Etamin
17 57
Extra Credit: Show stick figures for Cas, Cep, Lyr, and the dippers.
Etamin
Ras Algethi
Restaban
Kornephoros
Zeta
Alphekka
Nekkar
Arcturus
Muphrid
OTHER NAME
Observing the Sky
AOD 10/15/2007
6.5 m
16.3 m
July 25
+20°
-15°
November 4
4°
4° W
3°
2°
1°
1°
2°
1.5° E
3°
4°
Diagram adapted from Nicastro, Anthony J., Laboratory Astronomy: Experiments and Exercises, USA: Wm C. Brown Publishers, 1990
Page 2
Observing the Sky
AOD 10/15/2007
6)20 Using the Analemma, and the equations for the azimuths of rising and setting and the length of the
day,
⎛ sin δ ⎞
Arise = cos −1 ⎜
⎟
⎝ cos λ ⎠
Δt =
Aset = 360 − Arise
degrees
degrees
2
cos −1 ( − tan λ tan δ ) hours
15
find the rising and setting azimuths and the length of the day for the following stars:
STAR
OTHER NAME
α Boö
Arcturus
RIGHT
14h16m
h
m
η Oph
Sabik
17 10
Sol
DATE
July 25
8h18m
Sol
November 4
DECLINATION
ASCENSION
h
14 37
Arise
CANTON, NY (λ = 44° 36’ = 44.6°)
Aset
Δt
+19° 12 = 19.2°
62.5°
297.5°
14.6 h = 14h 36m
-15° 44’ = -15.7°
112.3°
247.7°
9.85 h = 9h 51m
+20°
61.3°
298.7°
14.8 h = 14h 48m
-15°
111.3°
248.7°
9.96 h = 9h 57m
m
I’M ASTOUNDED BY
PEOPLE WHO WANT TO
“KNOW” THE UNIVERSE
WHEN IT’S HARD ENOUGH
TO FIND YOUR WAY
CHINATOWN.
- WOODY ALLEN
AROUND
7)6 On the dates given, at what clock time does solar noon occur in Potsdam at longitude 75° W?
DATE
DECLINATION
OF SUN
SUN’S POSITION AT CLOCK
NOON (DEGREES E OR W)
EARLY OR LATE FOR CLOCK NOON
July 25
+19° 12’
November 4
-15° 44’
1.5° E
4° W
6.3 min late
16.3 early
MINUTES BY WHICH SUN IS
CLOCK TIME OF SOLAR NOON
12:06:20 pm
11:43:40 am
8)6 La Coruña, Spain is located at 8o23’ W, yet it is in the same time zone as western Europe, centered at
15o E, 1 hour earlier than UT (shaded dark on the map).
60°N
a)4 When it is solar noon in La Coruña, what is the civil (clock) time?
15°W
0°
15°E
Solar noon at 1:33:31 pm
Show your calculations!
8°23’ = 8°+(23/60)° => 8.38° + 15° = 23.38° W of TZ meridian
23.38 x (4 min/degree) = 93.52 min = 93:31 minutes LATE
b)2 Is La Coruña in the most "natural" time zone?
Explain your answer.
If one thinks of having solar noon near clock noon, La Coruña
is way off! It should be in the UK’s time zone, but the Spanish
might then think they have to speak English!!
Page 3
45°N
La Coruña
Observing the Sky
9)10 Complete the following table for the phases of the moon :
ELONGATION
PHASE
degrees E or W
1st Quarter
Waning Crescent
RISING TIME
TRANSIT TIME
SETTING TIME
Noon
3 am
3 pm
6 pm
6 pm
9 am
9 pm
Midnight
6 am
Midnight
3 pm
3 am
90° E
~45° W
135° E
180°
90° W
Waxing Gibbous
Full
rd
3 Quarter
AOD 10/15/2007
MIDNIGHT
6 am
Noon
10)24 List the positions of the visible planets on December 15, 2007. Complete the table and plot their
positions at sunset on that day on the diagram.
OBJECT
PLANETARY
LONGITUDE
ATLAS
CHART #
CONSTELLATION
ELONGATION
(E OR W!!)
Sun ()
263
41
Ophiuchus
ZERO
Mercury (☿)
262
41
Ophiuchus
1° W
Venus(♀)
222
28
Libra
41° W
Mars (♂)
96
12
Gemini
167° W
Jupiter (♃)
269
41
Sagittarius
6° E
Saturn (♄)
159
26
Leo
104° W
Cool!
♃
E
♂
observer
looking south
W ☿
Sun’s PL
263°
_______
♀
♄
11)10 On a Spring Break (mid-March) overnight whale watch, your ship is caught in an unexpected squall and
knocked off course. Due to a lightning strike, the navigation equipment is destroyed. On deck it is dark.
The ship’s captain explains to you and your fellow whale-watchers that he does not know where you are and
you will have to drift until someone finds you. You notice that stars are starting to emerge from behind
the clouds and realize that you can figure out where you are because you are still carrying your battered
Field Guide to the Stars and Planets, you have a compass that also measures altitude angle, and your watch,
set to your home time zone of New York (Eastern Standard Time) has kept perfect time since it was given
to you at your graduation from St. Lawrence. With these tools, you measure Polaris’ altitude above the
northern horizon to be 18.5°. Also, you observe the transit of Spica at 1:22 am. Looking up the transit
time in your Field Guide, relieved to see that it happens to cross a grid line on that day, March 15, you see
the time it should transit. From these data, you then calculate your latitude and longitude.
18.5°
Altitude of Polaris _____
1:22 am
Observed transit of Spica ________
18.5°
Ship’s Latitude: __________
2 am
Expected Transit of Spica ________
75° W – 38 min x 1°/4 min = 75° - 9.5° = 65.5°
Longitude: ___________________________________________
Satisified you know where you are, you decide to sail to the closest island. To what island will you sail
and what language will you have to use there?
18.5° N, 65.5°W
Sail about 25 km SW to Fajardo,
Puerto Rico and speak Spanish!
Page 4
Observing the Sky
AOD 10/15/2007
12)6 Given that Calvin and Hobbes live in North America, what time does the orientation of the moon
indicate? (HINT: Which side of the moon is the light on? Is this the waxing or waning moon?) Is this a
likely time for a six year old to be out trying to imitate a firerly?
Light’s on the left so it is a WANING CRESCENT moon which
rises after midnight … this thin a crescent would rise after 3 am
so, no, a six year old should not be out!
13) For the following questions, refer to the Sky Gazer’s Almanac.
a)2 When did the most recent 3rd quarter moon occur? (date and time)
October 2nd at 10 pm EST or 11 pm EDT
b)2 When will the next new moon occur? (date and time)
October 11th at 12 am EST (5 UT on p. 351 in FG) or 1 am EDT
3
c) When is the next greatest elongation of Mercury? Is it eastern or western? Will it rise in the
morning before the sun or set in the evening after the sun?
November 8th at 10 am EST. Since it’s rising before the sun, it’s a western elongation.
d)6 What is the date of the Earliest sunset this year? When is the shortest day? Why are they not
the same?
The earliest sunset is on December 8th. The shortest day is December 21st. They are not
the same because of the analemma … the true sun is ahead of the mean sun in December
so actual solar events (eg. solar midnight) are ahead of mean solar events (clock midnight).
e)18 List the events that took place after clock midnight on August 19 (night of August 19-20).
TIME
EVENT
12:00 AM
Clock Midnight
12:04 am
Solar Midnight
1:23 am
Uranus Transits
1:34 am
Betelgeuse Rises
3:36 am
Morning Twilight
3:47 am
Sirius Rises
4:46 am
Upper Culmination of Polaris
4:50 am
Neptune Sets
5:14 am
Venus Rises
5:15 am
Sunrise
Page 5