MATERIAL YOU ARE EXPECTED TO KNOW FOR THE MIDTERM TEST IN 
ASTRONOMY 161. CHAPTERS REFER TO CHAPTERS IN ONLINE JOURNEY 
THROUGH ASTRONOMY (2-SEMESTER VERSION)

CHAPTER 1

This chapter is for setting things in historical perspective.  
I will not ask any questions from it on the midterm exam.

CHAPTER 2

Definition of celestial sphere, zenith, celestial meridian, 
ecliptic, plane of the ecliptic
The celestial coordinate system, including right ascension  
and declination
Celestial equator, north and south celestial poles
Relationship between angle of turn for the sky and time 
(e.g., 15 degrees per hour)
Definition of the equinoxes and the solstices
Difference between diurnal and proper motion on the celestial 
sphere
How east and west are defined on the celestial sphere 
(relative to the Sun)
Difference between a constellation and an asterism
Definition of the zodiac
The Bayer and Flamsteed systems for naming stars
Meaning of inferior/superior and inner/outer classifications 
of planets
Understand and be able to draw the aspects and phases diagrams 
for both inferior and superior planets
What were 7 planets of ancients?  How does this list differ 
from the modern list of planets?
What are the basic observational differences between stars and 
planets?
Why do stars "twinkle"?
What are direct and retrograde motion for planets on the 
celestial sphere?
What is the difference between sidereal and synodic periods 
for planets?
What is difference between sidereal and solar days.
What is precession of the Earth's axis?  How does it influence 
the location of the celestial pole and the equinoxes?
Why do sidereal and tropical years differ in their lengths?
How does the Gregorian calendar differ from the original Roman 
calendar?
Be able to describe in words and/or diagrams, the reasons for 
the seasons.
What causes the lag of the seasons?
Understand and know the length of  the synodic and sidereal 
periods for the Moon's revolution
Be able to diagram or describe in words the reason for the 
phases of the Moon
How much does the Moon appear to drift with respect to the 
constellations in a day?
Why are the Moon's rotational and revolutionary periods almost 
exactly equal?
What are librations of the Moon?
Be able to explain in words and diagrams the reasons for both 
solar and lunar eclipses
What do the words total, partial, annular, umbra, and penumbra 
mean for a solar eclipse?
What is a Saros cycle?
Describe what you would observe in the course of a total 
solar eclipse and a total lunar eclipse.

CHAPTER 3

Be able to describe Erastosthene's method for determining 
circumference of Earth
Be able to describe Aristotle's picture of the Universe
How were retrograde motion & varying brightness of the planets 
described in Ptolemaic universe?
What were Aristotle's "essences"?
What were epicycles and deferents?
What were the 3 fundamentally wrong ideas that underlay the 
Ptolemaic Universe?
How did the model of Copernicus differ from the Ptolemaic model?
How did the Copernican model explain varying brightness of the 
planets and retrograde motion?
What were some of the objections to the heliocentric model of 
the solar system raised against Aristarchus?
Be able to list the most important observational contributions 
of Brahe to modern astronomy
Know the definition and significance of parallax. 
Why was absence of observed parallax for a comet and supernova 
by Brahe important?
Be able to state and explain (using diagrams, if necessary) 
Kepler's 3 laws

CHAPTER 4

What were some important contributions of Galileo to 
astronomy?  Why were they important?
What was Galileo's concept of inertia?
How did the dynamics of Galileo differ from that of Aristotle?
Understand the definition of a vector, of velocity, and of 
acceleration
Be able to state and explain Newton's 3 laws of motion
Be able to state and explain the universal law of gravitation
Be able to define, with diagrams and equations if necessary, 
the center of mass for a system
What is the relationship between weight and mass?
What are the conic sections?  How are they important for 
gravitational orbits?
What is a gravitational perturbation?  How can they be used 
to predict the existence of new planets?
What are the two fundamental ideas that lie at the basis of 
the special theory of relativity?
What is time dilation?
What is space contraction?
How are energy and mass related in relativity?
Describe the role of the speed of light in special relativity
What is the principle of equivalence in general relativity?
What are the basic tests of general relativity versus 
Newtonian gravity?  Explain the results of the tests.
What is the relationship of gravity and spacetime curvature 
in general relativity?

CHAPTER 5

Know the general regions of the electromagnetic spectrum.  
What are the colors of the visible spectrum in order of 
increasing wavelength.
What is the relationship of wavelength and frequrency and 
energy for a light wave?
What are refraction, diffraction, and dispersion?  Be able to 
draw schematic diagrams illustrating them.
Be able to explain the Doppler effect, using diagrams if 
appropriate.  What is the relationship between the shift in 
wavelength and the radial velocity?
What are redshifts and blueshifts?
Understand the inverse square law for light intensity.  
Be able to work simple problems using it.
Be able to sketch the curve (with labels) corresponding to 
the Planck radiation law (but you don't have to  memorize 
the equation)
What is the significance of the Wien law?
What is the significance of th Stefan-Boltzmann law?
Be able to define the basic components of an atom
What is an isotope?
Be able to sketch and describe the Bohr model of the atom
What is ionization?  What is a plasma?  How are ions labeled?
What are molecular rotations and vibrations?
What is a spectrum of light?
Understand and able to explain the difference between contiuum, 
emission, and absorption spectra, including the different 
conditions under which they can arise in a gas
What are the hydrogen spectral series?  Be able to use the 
Bohr model of the atom to explain  how they can arise.
What are the lines of the Balmer series for hydrogen?
What is the Zeeman effect?  How is it related to magnetic 
fields?
What is nonthermal emission?
How does synchrotron radiation arise?

CHAPTER 6

What are some of the observational limitations of the human 
eye that telescopes can overcome?
Be able to describe, using diagrams if appropriate, how 
refracting and reflecting telescopes work
What are some of the things that effect "seeing conditions"?
What does one mean by "adaptive optics"?
Why is the resolution of a telescope important?
Why is the light-gathering power of a telescope important?
What are charge-coupled devices?  Why are they important in 
astronomy?
What are the 3 most important roles played by computers in 
modern astronomy?
Be able to describe the origin of the 21 cm hydrogen spectral 
line and why it is important
What is long-baseline interferometry?  Why is it important?
What is the general relationship between resolution and 
wavelength for a telescope?
What do we mean by "atmospheric windows"?  
What are the significant atmospheric windows for Earth's 
atmosphere?
What are the advantages of telescopes in space above the 
atmosphere?
What are neutrinos?
Why are neutrinos important in astronomy?
What are cosmic rays?

CHAPTER 7

Have a general understanding of the radii, eccentricities, 
masses, and orientations for the planetary orbits in the 
Solar System (not so much memorizing the numbers, but 
understanding the qualitative similarities and differences 
among the planets for these quantities.
What is angular momentum?  Why is it important?
Be able to explain the basic features of the nebular hypothesis
What data support the nebular hypothesis?
What are protoplanetary disks?
What is the "Hot Jupiter Problem" for extrasolar planets?
How are extrasolar planets detected?


CHAPTER 8

Be able to diagram and describe the basic divisions of the 
interior of the Earth
What are the basic kinds seismic waves and their importance?
How have seismic waves been used to learn about Earth's 
interior?
What is geological differentiation?  What causes it?  Why is 
it important?
What is the lithosphere, the asthenosphere, the mantle?
Be able to describe the basic mechanism of plate tectonics
What is some of the evidence supporting the theory of plate 
tectonics?
How are volcanoes and earthquakes explained using plate 
tectonics?
What are the basic layers of the atmosphere and their 
characteristics?
What is the ozone layer?  Why is it important?
Why do chloroflourocarbons appear to be dangerous for the 
ozone layer?
What are the theories of how Earth's atmosphere originated?
What is the coriolis force?  What effect does it have on 
objects in motion?
Be able to explain the roles of solar heating and the 
coriolis force in Earth's weather
What are cyclones, anticyclones, and fronts?
Be able to sketch the field lines of Earth's magnetic field
What are the van Allen Belts?  Where are they?
What is the source of Earth's magnetic field (qualitative 
only; details are not very well understood)?
What is the magnetosphere?
Be able to explain how auroras arise