THE UNIVERSITY
OF QUEENSLAND
DEPARTMENT OF PHYSICS
PH223 Astronomy A Midsemester
exam 1997
Who of the following early Greek astronomers,
a) Aristarchus, d) Apollonius,
b) Aristotle,
e) Eratosthenes,
c) Hipparchus,
51 c discovered the effects of (but not reason for)
precession,
52 e recognised the significance of seeing sunlight
on the bottom of a well (Syene, Egypt),
53 c devised a system of stellar brightnesses now
known as the magnitude system,
54 a first measured the relative sizes of, and distances
to, the sun and moon,
55 c compiled a star catalogue of about 850 entries?
Who of the following early astronomers
a) Copernicus d) Newton
b) Galileo
e) Tycho
c) Kepler
56 b First saw moons around another world, the
Galilean satellites
57 d knew most about the rings of Saturn, most
recent – came after Huygens
58 a Wrote De Revolutionobus;
59 e first realised comets were objects more distant
than the moon, no parallax
60 d Wrote The Principia?
Which of the following orbital elements,
a) semi major axis,
d) time of perihelion passage, T,
b) anomaly,
e) eccentricity,
c) inclination of orbit plane to ecliptic plane,
61 e is very nearly but not quite zero for the earth, oops!
62 e gives the shape of an orbit,
63 d determines when a body like Venus is closest
to the sun,
64 c causes the planets to be found away from the
ecliptic,
65 b is not considered to be a formal orbital element?
Near which of the following dates pertaining to astronomical significance
a) 1 January
d) 22 June
b) 22 January e) 22 September
c) 22 March
66 c is Venus near superior conjunction (1997),
67 c is Easter related to, first
full moon after vernal equinox…
68 e do sidereal clocks and your wristwatch agree,
69 d is the zenith distance of the sun 51 degrees
at noon, solstice, sun farthest north
70 a is earth closest to the sun (perihelion
passage),
71 e will the azimuth of sunrise next be 90
degrees , happens on equinoxes
72 e does the sun appear to cross the celestial equator
from north to south,
73 e does the sun rise due east when the sidereal
time is 6AM,
74 a does the sun have a declination -23.5 degrees
, Jan 1 is closest to Dec 22.
75 d will the azimuth of sunset be most north of due
west?
Which of the following possible orbits,
a) parabolic d)
hyperbolic
b) spiral
e) elliptical
c) circular
76 e did Kepler first discover, Keplers’ first law
77 c is the orbit of a body having constant speed, Kepler’s
second law
78 b is the orbit of a body whose angular momentum is not constant,
Kepler’s third
79 e is the orbit of the earth, all solar system objects
are this
80 d pertains to a body visiting the solar system from beyond the solar
system?
The Mariner 10 spacecraft has (by design) a period nearly exactly
twice as long as that of Mercury (so its p=2x88 days or 0.482y) and, hence,
enjoys repeated encounters every perihelion passage. Assuming (bad!) Mercury
has a circular orbit with a=0.387AU, what is
81 the semi major axis of Mariner 10 (in AU), a=p2/3=0.4822/3=0.61
--d
a) 0.3 b) 0.4
c) 0.5 d) 0.6 e) 0.7,
82 the perihelion distance of Mariner 10 (in AU), same
as Mercury! --b
a) 0.3 b) 0.4
c) 0.5 d) 0.6 e) 0.7,
83 the aphelion distance of Mariner 10 (in AU), 2a-perihelion=1.23-0.387=0.84
a) 0.3 b) 0.4
c) 0.5 d) 0.6 e) 0.7,
so e is nearest
84 true during rendezvous: --b
a) the objects have the same speed,
b) Mariner 10 moves faster than Mercury,
c) Mercury moves faster than Mariner 10,
d) Mercury moves faster before and slower after,
e) Mariner 10 moves faster before and slower after;
85 true when Mariner 10 is at aphelion: --c
a) the objects have the same speed,
b) Mariner 10 moves faster than Mercury,
c) Mercury moves faster than Mariner 10,
d) Mercury moves faster before and slower after,
e) Mariner 10 moves faster before and slower after.
86 The bright planet well up in the east after sunset is Mars
--c
a) Mercury, b) Venus, c) Mars, d) Jupiter, e) Saturn.
87 At this moment the Moon's phase is best described as --e or, grudgingly, b--
a) last quarter, d) waning gibbous,
b) nearly new, e) waxing
crescent.
c) nearly full,
88 At 8PM tonight, the southern cross (Crux) is --b
a) below the horizon,
d) high in the west,
b) high in the southeast, e)
low in the west.
c) in transit,
89 The bright planet high in the morning sky is Jupiter,
--d
a) Mercury, b) Venus,
c) Mars, d) Jupiter, e) Saturn.
90 The planet having a nearly 12 year sidereal period is Jupiter,
--d
a) Mercury, b) Venus,
c) Mars, d) Jupiter, e) Saturn.
91. Castor shines at magnitude 1.6 and Pollux at magnitude 1.1 so the two
stars differ in brightness by a factor of
10.4(1.6-1.1)=1.58, --b
a) 1.45, b) 1.58,
c) 2.51, d) 3.16, e) 12.02
92. The brightest star in the sky (excluding the sun of course) is Sirius
which shines at magnitude -1.5 and is thirteen times brighter than Mimosa.
Mimosa shies at magnitude dM=2.5log(13)=2.78 add to -1.5
to get 1.28, --c
a) 0.25 b) 1.05,
c) 1.33 d) 3.31 e) 2.8
93 If a star rises tonight at 2100, one month from now it will rise at
two hours earlier, --a
a) 1900, b) 2000,
c) 2200, d) 2300, e) 2030.
94 Roche's limit is or deals with tidal disruption occurs
at about 2.5 primary radii…, --a
a) tidal disruption
d) the maximum size a planet can attain,
b) the Roche lobe in a contact binary,
e) gravitational radiation.
c) the closest approach in a restricted three
body orbit,
95. Sidereal time is --b
a) the local hour angle (LHA) of the sun,
b) the local hour angle of the vernal equinox,
c) sundial time minus twelve hours,
d) very nearly the hour angle of Sirius,
e) the local hour angle of 0h RA plus twelve hours.
96. The semimajor axis of Neptune in AU is
10,20,30,40 for Sat,Ura,Nep,Pl, --c
a) 3.16, b) 10.0
c) 31.6, d) 100., e) 316.
97. The period in years of a comet having a semimajor axis of 50 AU is
about 503/2=353.6
a) 3.16, b) 10.0
c) 31.6, d) 100., e) 316.
--e is closest.
98. By what factor is Ceres (typical asteroid) brighter at opposition than
at conjunction?
Bode’s rule
gives asteroids at 2.8 so factor is [conjunction/opposition]2=[(2.8+1)/(2.8-1)]2=4.46
--b
a) 2, b) 4,
c) 8, d) 16, e) 32.
99. The magnitude of Ceres changes from opposition to conjunction by
2.5log4.46=1.62 --c
a) 0.5, b) 1.0,
c) 1.5, d) 2.0, e) 3.0 magnitudes.
100. The orbital eccentricity of a typical comet is --b
a) 0.1, b) 1.0,
c) 0.01, d) 0.5, e) 1.25.
That's all, folks!