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Astronomy:
Telescopes and
Studying the Stars
2012-2013
Astronomy:
Telescopes and Studying the Stars
I.
Telescope Overview
II. Read Chapter 1, Section 3 (pages 18-23)
III. Directed Reading Worksheet (questions 1-20)
IV. Making a Simple Lens
V. Lenses and Mirrors
VI. Reading Road Map for “Stars” (p. 98 – 104)
VII. Is White White?
VIII. Bill Nye Video and Worksheet
IX. Astronomy Alphabet Soup
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Telescope Overview
Astronomy is the study of all physical objects beyond Earth. Before astronomy became a
science, people in ancient cultures used the seasonal cycles of celestial objects to make calendars
and organize their lives. Over time, some people began to observe the sky for less practical
reasons – mainly to understand Earth’s place in the universe. Today, astronomers all over the
world are using new technologies to better understand the universe.
Galileo, in the year 1609, was one of the first people to use a telescope to make scientific
observations of celestial bodies. Although his telescope was very simple and was equivalent to
only that of most modern binoculars, some of Galileo’s discoveries led him to determine that the
planets are not just dots of light in the night sky; instead, the planets are physical bodies like the
Earth. This doesn’t seem like much to us during the 21st century but 400 years ago it was a
major revelation!
For professional astronomers and amateur stargazers, the telescope is the standard tool for
observing the sky. A telescope is an instrument that collects electromagnetic radiation from the
sky and focuses (or concentrates) it for better observation. There are different kinds of
telescopes: optical telescopes and non-optical telescopes.
The first telescopes were optical telescopes. This was what Galileo used. If your Uncle Vong
owns a telescope or if your parents buy one at Gander Mountain, it’s going to be an optical
telescope. An optical telescope is the kind you look through with the naked eye to see distant
objects. In its most basic form, an optical telescope consists of two lenses and a tube in which
the lenses fit.
Non-optical telescopes are relatively new inventions of science. They include radio telescopes,
ultraviolet telescopes, infrared telescopes, gamma-ray telescopes, and X-ray telescopes. These
kinds of telescopes are used only by research scientists (although research scientists also use
some optical telescopes). The “VLA,” a radio telescope located in New Mexico, consists of 27
separate “dishes” that can be moved around on tracks similar to railroad tracks. Each dish is
25 m in diameter. When spread out to their maximum distance, they work as a single telescope
that would be 30 km (nearly 19 miles) across! Keep in mind, though, that you can’t “see”
through a non-optical telescope like through an optical telescope. Non-optical telescopes don’t
detect electromagnetic radiation in the visible spectrum. These kinds of telescopes need to be
connected to special cameras and computers so that the incoming radiation can be processed and
turned into a form that we can actually see.
Optical telescopes come in two different styles – refracting telescopes and reflecting
telescopes. Based on what you already know about refraction and reflection, can you figure out
what each one is like or what each one consists of? Think about it for a minute and discuss it
with a classmate. On the bottom of this page, sketch what you think each telescope might
look like on the inside. (Remember the basic components of an optical telescope and be sure to
label your diagrams!)
Refracting telescope
Reflecting telescope
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Diagrams of refracting and reflecting telescopes are shown below. How do your sketches and
ideas compare to the real thing? Were you on the right track?
_________________________________________________
_________________________________________________
_________________________________________________
Refracting telescope:
Reflecting telescope:
Most professional astronomers and serious amateurs prefer reflecting telescopes. Based on the
diagrams above and what you already know about glass, visible light waves, and refraction, can
you come up with any reasons why a reflecting telescope might be better than a refracting
telescope?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
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Name: __________________________________
Per. _______
Questions:
Answer the following after reading the “Telescope Overview.”
1. Without looking back at the reading, write your own definition of astronomy.
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
2. How did ancient cultures first use the sky?
___________________________________________________________________________
___________________________________________________________________________
3. Why do scientists study the sky?
___________________________________________________________________________
___________________________________________________________________________
4. Who was one of the first people to put a telescope to scientific use? ____________________
5. How many years ago did this person first begin using the telescope to make scientific
observations of the sky? __________________
6. Would you be more likely to use an optical or non-optical telescope?
___________________________________________________________________________
7. Do you consider an optical or non-optical telescope to be more technologically advanced?
__________________________________________________________________________
8. What is the main difference between a refracting telescope and a reflecting telescope?
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
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Name: _________________
Directed Reading Worksheet
Chapter 1, Section 3 (P.18-23)
1. What do telescopes do with electromagnetic radiation?
_________________________________________________________
_________________________________________________________
_________________________________________________________
2. The simplest telescope contains two lenses-an objective lens and a lens
located in the ___________________ of the telescope.
3. As many as ___________________ stars are visible in the sky without a
telescope.
4. Why do most professional astronomers use reflecting telescopes?
_________________________________________________________
_________________________________________________________
_________________________________________________________
5. Which of the following is NOT true of reflecting telescopes?
a. They use curved mirrors to collect light.
b. Flaws in the glass don’t affect the collected light.
c. Different colors of light are focused in one place.
d. Lenses gather and focus light.
6. Why is a mountaintop the best place on Earth to put a telescope?
_________________________________________________________
_________________________________________________________
_________________________________________________________
7. The clearest images of objects in deep space are produced by a telescope in
space. True or False?
8. Our bodies sense infrared radiation as _____________________.
9. James Clerk Maxwell discovered that light is a form of
________________ radiation.
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Each of the following wavelengths is either blocked or unblocked by the Earth’s
atmosphere. In the space provided, write B if the wavelength is blocked and U if
the wavelength is unblocked.
10. ______ infrared radiation
11. ______ radio waves
12. ______ gamma rays
13. ______ X rays
14. A different type of telescope or ___________________________ is
needed for each type of electromagnetic radiation.
15. In figure 24, what is the cloudlike object that goes across each picture?
_________________________________________________________
_________________________________________________________
Mark each of the following statements True or False.
16. ___________ Optical telescopes are much larger than radio telescopes.
17. ____________ Small quantities of radio radiation reach Earth from
objects in space.
18. Why can chicken wire be used as the surface of a radio telescope?
_________________________________________________________
_________________________________________________________
_________________________________________________________
19. In the ___________________ __________________
__________________ many radio telescopes are linked to work as one
giant telescope.
20. The Chandra telescope is the most powerful infrared telescope ever built.
True or False?
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Making a Simple Lens
Have you ever wondered what it is about a magnifying lens that makes it magnify?
In this activity you’ll make a simple magnifying lens with a single drop of water!
Materials:
Piece of newspaper
Piece of overhead transparency
Beaker of water
Plastic pipette
Paper toweling
Procedure:
1. Spread the piece of paper toweling on your table.
2. Lay the cut out piece of newspaper on the paper toweling.
3. Place the piece of overhead transparency on top of the newsprint.
4. Using the plastic pipette, carefully place a drop of water on top of the
transparency. Don’t let the tip of the pipette touch the transparency or the
water on the transparency!
5. You should look at the newsprint to see if its appearance has changed.
6. Look at the water drop from its side. Notice what shape it has.
7. Repeat steps 5, 6, 7, and 8 over adding one drop of water at a time.
8. Keep doing this as long as you can make the newsprint’s appearance change.
Challenges:
1. Place a drop of water on the transparency and then pick up the transparency
and move it away from the newspaper. What happened?
2. Attempt to place an air bubble inside of a water droplet. What happened?
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Name: _________________________
Questions:
9. Sketch the shape of the water drop while it was on the transparency. In other
words, sketch the water drop as it appeared while looking at it from its side,
not while looking down on it.
10.What did the water drops do to the newsprint’s appearance?
________________________________________________________________
________________________________________________________________
11.Why do you think the water drops made the newsprint appear larger?
________________________________________________________________
________________________________________________________________
________________________________________________________________
12. Imagine that you are the first person in the world to have ever discovered this
interesting characteristic of water. What could you have done with your
knowledge? What “tools” could you have invented?
________________________________________________________________
________________________________________________________________
_______________________________________________________________
13.Water isn’t always very easy to work with, especially in this way. What do you
think you could possibly use instead of water to achieve similar results?
________________________________________________________________
9
Lenses & Mirrors
Have you ever gone through a fun house and noticed how your appearance changes when you
look at yourself with different shaped mirrors? Have you ever looked through a telescope or
binoculars? These devices are made possible through the use of lenses and mirrors. Lenses and
mirrors cause electromagnetic waves to be either refracted (bent) or reflected (bounced off)
and this can cause images to appear larger, smaller, or even distorted.
Materials:
convex lens
concave lens
plane mirror
concave mirror
convex mirror
metric ruler
Concave Lens
Concave Mirror
Plane Mirror
Convex Mirror
Convex Lens
Procedure:
After you have the different lenses and mirrors at your desk, identify them with the
diagrams in figure 1. If you are unable to identify them ask your teacher for help.
Questions:
1. Which two of the above can make objects appear larger?
___________________________________
__________________________________
2. List two of the above that can make objects appear smaller.
___________________________________
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__________________________________
3. After experimenting with the various lenses and mirrors, complete the table below:
Hold Lens or Mirror a distance of
10 –15 cm from an object with writing
Type of Lens
or Mirror
Size of Image
(Larger, Smaller,
Same)
Image
Appearance
(Right-side up,
Upside down,
Backwards)
Hold Lens or Mirror at arms length
and look at a distant object with
writing
Image
Appearance
Size of Image
(Right-side up,
(Larger, Smaller,
Upside down,
Same)
Backwards)
Concave
Mirror
Concave
Lens
Convex
Mirror
Convex Lens
Plane
Mirror
4. What type of lens would be used to make a magnifying glass?
________________________________________________________________________
5. What type of mirrors do stores use to help prevent shoplifting?
________________________________________________________________________
6. What is meant by the statement, “Mirrors cause images to be reversed”?
________________________________________________________________________
________________________________________________________________________
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Name: _____________________________
Per.: _______
Reading Road Map
for
“Stars” p. 98-104
Use this Reading Road Map to guide you through the “Stars” section in your
Astronomy textbook. The “Location” category tells you what to read; the “Speed”
category tells you how carefully to read it; the “Mission” category tells you what
you have to answer in the provided space. Have a great trip!!
Location
Speed
Mission
1. What are stars?
Top of p. 98
2. How do astronomers study stars?
3. Is Betelgeuse hotter or cooler than Rigel?
“Color of Stars”
(p. 98)
4. How can you tell?
“Composition of
Stars”
(p. 98)
5. In what way is a spectrograph similar to a prism?
6. A star, therefore, produces a __________________ with various
lines in it.
“Hot, Dense
Gas”
(p. 99)
7. Emission lines are ….
“Making an ID”
(p. 99)
8. If you’re a scientist looking at a gas through a spectroscope and
you see 2 green stripes and no red or orange stripes, what gas(es)
would you probably not be looking at?
Figure 2
(p. 99)
9. T or F A star’s atmosphere is cooler than the star itself.
“Trapping the
Light”
(p. 99)
“Cosmic
Detective Work”
(Figure 3 p. 100)
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MINIMUM
SPEED
80
10. An absorption spectrum is produced when ________________
passes through a ________________ gas.
11. Identify the element in the gas by comparing the position of
the dark lines in its spectrum with the bright lines in Figure 2.
Figure 3
(p. 100)
12. Stars were originally classified by (choose the best!)
a. How big they were
b. What gases they contained
c. Where they were located
13. Stars are now classified by…
“Classifying
Stars”
(p. 100)
“Differences in
Temperature”
(p. 100-101)
14. The hottest stars are what color?
“Differences in
Brightness”
(p. 101)
16. The magnitude of a star refers to how _____________ the star
is.
“How Bright Is
That Star?”
(p. 102)
17. Do you think all the street lights in the picture are all of the
same actual brightness? In other words, do you think they all
have the same kind of light bulb in them?
15. The hottest stars contain what element?
“Apparent
Magnitude”
(p. 102)
18. Does the closer light in Figure 5 have an apparent magnitude
greater or lesser than the light farthest away in the picture?
“Absolute
Magnitude”
(p. 102)
19. Do you think the lights in Figure 5 have absolute magnitudes
that are fairly equal?
20. What is a light year?
“Distance to the
Stars”
(p. 103)
“Motions of
Stars”
(p. 103)
“Apparent
Motion”
(p. 104)
“Actual Motion”
(p. 104)
21. Why do astronomers use light years as a unit?
MINIMUM
SPEED
80
22. Why do we see different stars at different times of the year?
(Looking at the bottom of Figure 6 might help you understand
this.)
23. The sun and stars appear to move across Earth’s horizon
because Earth is _________________.
24. The actual movement of stars is hard for us to observe because
they are soooooo _____________ away.
13
Is White White?
White light is made up of many different colors and these colors depend on the wavelength of
the light. Light, however, that appears white might not be made up of exactly the same
wavelengths as other light that appears to be white. Scientists have also learned that different
chemical elements and combinations of chemical elements produce light made of different
wavelengths of visible light.
Instead of using a prism to separate out the different colors (wavelengths) that make up the light,
scientists use a spectroscope. How does a spectroscope cause light to separate out into its
various colors (wavelengths)? It uses diffraction. Diffraction is simply the bending (and
separation) of light as it travels through a very narrow slit. Different wavelengths bend different
amounts as they travel into a different medium? Different wavelengths do the same thing when
they travel through a tiny slit. Your spectroscope has thousands of tiny slits in it!!!! This makes
the light separate a lot so that it’s easy to see the different colors.
How do you think astronomers can tell what chemical elements stars are made up of when they
can’t get anywhere near the stars? They use spectroscopes! It isn’t always easy, though, because
stars are made up of combinations of elements so it actually turns out to be a puzzle to figure it
all out.
Materials:
 Spectroscope
 Various Light Sources
 Colored Pencils (ROYGBIV)
Procedure:
1. Look at the light source through the spectroscope. Follow your teacher’s instructions on how
to properly use the spectroscope.
2. Color in the box to match what you see through the spectroscope. If the colors blend into
one another, make sure you show that. If the colors are separate lines, make sure you show
that, too. If some colors are stronger or weaker, show that, also. In other words, try to copy
exactly what you see through the spectroscope!
1. Sunlight or Incandescent Light Bulb
R
O
Y
G
B
I
V
I
V
2. Fluorescent Light (Ceiling Lights)
R
14
O
Y
G
B
3. Yellow Bug Light
R
O
Y
G
B
I
V
O
Y
G
B
I
V
Y
G
B
I
V
Y
G
B
I
V
Y
G
B
I
V
I
V
I
V
4. Ne (neon)
R
5. N (nitrogen)
R
O
6. H (hydrogen)
R
O
7. He (helium)
R
O
8. ____________________________
R
O
Y
G
B
9. ____________________________
R
O
Y
G
B
10. Did you notice the numbers in your spectroscope? What do you think they are for? Discuss
this with a classmate and write your answer below.
______________________________________________________________________________
______________________________________________________________________________
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Name: _____________________
“Outer Space”
(Bill Nye video)
1. Most of what we’ve learned about outer space we’ve learned the same way
that people have learned about it for centuries – by
_____________________________________________________________.
2. By looking at the stars, we’ve learned about ___________ ___________.
3. Everything “out there” is made of the _____________ _______________
as we are.
4. Some groups of billions of stars look to us like single stars because they’re
so _______________ _______________ .
5. Light travels _______________ kilometers every second. This is about
three-fourths of the distance to the moon in one second!
6. Things in the universe are so far apart that it can take light
_______________ and _______________ of years to get from one place
to another.
7. A light year is the _______________ that _______________ travels in
one year.
8. Light travels about _______________ kilometers in one year.
9. Some of the stars we can see right now might not even _______ ________.
10.A constellation is a _____________________________________________
that we’ve given a name to help us find certain stars or to recognize them.
11.One of the easiest stars to find in the northern hemisphere is the
_______________ _______________ , sometimes called ____________ .
12.Eventually, in about _______________ years, Earth’s northern axis will be
pointing to the star Vega instead of _______________ .
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13.Each star is like a _______________ .
14.Astronomers use astrolabes to find out about the _______________ of stars
and to find _______________ .
15.The goal of scientists in general, and astronomers in particular, is to
___________________________________________________________ .
16.About _______________ years ago, a man named Eratosthenes figured
out that Earth is _______________ and he was able to calculate the
_______________ of Earth.
17.The ingredients to make virtually anything in the universe are __________.
18.Atoms come from _______________ .
19.Water is _______________ - which is _______________ parts H
(hydrogen) and _______________ part O (oxygen).
20.To make all the different kinds of atoms, you need the force of
_______________ stars and _______________ of years.
21.We are made of the same “stuff” as _______________ .
22.We have to study stars to understand what __________________________.
23.Since this video started, the light coming out of the television has traveled
about ______________________________ kilometers.
17
Name:_______________
Astronomy Alphabet Soup
Materials: Paper & Pencil
Procedure:
1.
Here are 64 letters:
M, A, N, N, T, S, Y, O, O, L, M, E, A, D, L, G, Y, T, S, U, P, L, R, A, N, R, T, S,
M, A, N, M, E, O, R, O, O, E, X, A, A, C, O, N, E, T, N, O, O, C, S, T, L, A, T,
E, R, T, I, O, I, S, E, T.
2. The goal is to unscramble the letters to make ten astronomy-related words
(Hint: the first word is in these instructions). You can unscramble the letters
using a single sheet of paper and a pencil, but it may be easier if you write each
of the letters on a separate slip of paper and then arrange the slips of paper.
3. Some of the words are easy; others are a little harder. Aside from the first
word, all the words are natural objects in space (heavenly bodies). You must
use up all the letters.
Answers:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
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M A N N T S Y
O O L M E A D
L G Y T S U P
L R A N R T S
M A N M E O R
O O E X A A C
O N E T N O O
C S T L A T E
R T I O I S E
T
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