STUDY GUIDE FOR PART 1 (ASTRONOMY)
Introduction and Early Development
INTRODUCTION:
What is Astronomy? It is the science which describes the celestial bodies according to
their locations, sizes, motions, constitutions, and evolutions.
Astronomy, as the definition states, is a science, and so we will study astronomy from the scientific point of view.
The first step in the scientific method is to specify the problem. Our definition of astronomy does this in a general
way. The second step in the scientific method is the observation of events and gathering of data. The third step is
the making up of a theory that tries to account for the past observations and also tries to predict future events. This
theory always involves assumptions. Sometimes these assumptions are made consciously by the scientist, and
sometimes they are made unconsciously. The fourth step is the actual comparison of theory to those observations
of events both past and predicted. This fourth step is a continuing process and goes hand in hand with step two, the
gathering of data. Whenever a theory cannot account for all the data, then it must be modified or abandoned and a
new theory tried.
In this first part we will look at the sky with our unaided eyes and gather that same data that the ancients
gathered. Then we will look briefly at the theories that have been proposed in the past to explain that data. In Part II
we will consider the nature of light and the basic tools that we have used to tremendously expand our collections of
data and test our theories. Then in Parts III, IV, and V we will use this additional data to help us understand our
present theories of our solar system, our galaxy, and our universe.
A. The Scientific Method
[text: Foundations I, section 1]
OUTLINE:
1. The scientific method
(1) Define the problem (what are you concerned with?)
(2) Observe (gather data)
(3) Try to explain (relate, hypothesize, then predict)
(4) Test the theory (observe - back to step 2!)
Study Questions for Part A:
*1. List the four steps in the scientific method.
B. Basic Data
[text: Ch. 1, sections 1-5]
OUTLINE:
1. Definitions, terms, and notations
a) zenith (directly overhead)
b) meridian (north-south line across sky - through the zenith)
c) ecliptic (path of the sun through the stars)
d) constellations of the zodiac (the twelve constellations that fall along the ecliptic)
e) right ascension (celestial longitude, 0-24 hours; 0 hrs is location of sun on ecliptic on
first day of spring)
f) declination (celestial latitude, from +90° [above north pole: North star] thru 0° [celestial
equator] to -90° [above south pole])
