Activity 1 Introduction to Telescopes
Standards (see Appendix A):
- Science Content Standards: A. Science as Inquiry, E. Science and
Technology, G. History and Nature of Science.
- Mathematics Standards: Representation.
- Technology Tools: Productivity; Research; Problem Solving and
Unifying Concepts: Form and Function; Systems; Order and Organization.
The students will begin to understand how telescopes are tools of the
astronomer. Telescopes function as systems, with mirrors and/or lenses
that gather and focus light from distant sources in the sky to create images
which can be seen through an eyepiece. Astronomers
attach cameras or detectors to telescopes in order to record images and collect
data for analysis.
This activity provides students with experience looking at different kinds of
telescopes sufficient to begin exploring the questions:
are the different parts of a telescope?
are there different kinds of telescopes?
is needed to sense or record data from a telescope?
do telescopes assist astronomers in making observations of far away objects
that appear very faint or small?
Galileo was the first scientist to use telescopes for the study of astronomy. The story is told that Galileo was
made aware of a new device apparently from Amsterdam invented by an optician,
which allowed objects at a distance to be viewed more easily. Galileo took the idea of the telescope
and began to make technological improvements on it. He soon had a device that he could market to politicians and
to the merchants of Venice. They
were able to see faraway ships at sea approaching the land. Some of these ships could have been enemies; telescopes
provided advance warning of attack. Other
ships were carrying goods for trade. With
the help of the telescope, merchants could manipulate the price of commodities
and make larger profits off each shipload of goods. The merchants were grateful enough to Galileo that they set
him up with a good income and a university chair.
Galileo used his telescope to make many new discoveries about the solar
system. He discovered craters on
the moon, phases of Venus, the moons of Jupiter, and sunspots. He used his discoveries to support
Copernicus's heliocentric model of the universe.
Use the web to research Historical Telescopes:
This site contains a brief history of the building of telescopes and the
people who did the construction. http://es.rice.edu:80/ES/humsoc/Galileo/Things/telescope.html.
Go straight to the source, the Museum of Science in Florence Italy, for
information about Galileo. http://galileo.imss.firenze.it/museo/b/egalilg.html
Recommended Literature: Galileo’s
Daughter by Dava Sobel, Walker & Company, 1999. http://www.galileosdaughter.com/home.shtml
SAFETY: Never point a telescope at the Sun. Do not look through magnifiers,
binoculars or a telescope pointed at the Sun.
(The only safe way to view the sun is through specialized solar filters
placed over the large end of the telescope, filtering the light before it passes
through the telescope optical systems.)
Students will experiment with
telescopes and imaging systems throughout this curriculum, where concepts and
technical vocabulary concepts will be developed.
This lesson is meant only as exploratory.
The following summary is provided as background for the teacher.
Telescopes are systems containing
- a primary or objective mirror or lens
- structures to hold the mirrors and/or lenses in place
- a tube for shielding outside light
- systems for attaching and adjusting eyepieces or cameras at the focus.
- systems for pointing the telescope and in some cases tracking objects in
The purpose of a telescope system is
- collect light to make bright images
- magnify or make images look larger
- focus images clearly
- resolve detail in images
- find and point to objects in the sky
- Aperture describes the size (usually diameter) of a primary lens or
- Focal Length describes the distance from the primary lens or mirror to the
point or plane of focus.
- Focal Ratio (f/#) is calculated by dividing the focal length by aperture
- Image is the “picture” created by the optical systems, either detected
by a person’s eye at the eyepiece or by a camera at the focal point.
- Magnification, for purposes of visual observing, is calculated by dividing
the focal length of the telescope by the focal length of the eyepiece.
- When pictures are taken with telescopes, image size and image scale are
described by measuring the actual size of the image on the detector
and as an angle per millimeter or pixel.
- Field of View (FOV) refers to the angular measure of the sky seen by an
observer at the eyepiece or captured by a camera.
Gather a picture or pictures of the sky.
one or more posters, pictures or slides of the night sky for the students or
entire class to view.
Check NASA website for location of Teacher Resource
here is a Picture of the Milky
Way, taken by Richard Hackney, Director of Kentucky Space Grant
Hardin Planetarium & Astrophysical Observatory, http://www.wku.edu/ksgc
Western Kentucky University, Bowling Green, KY 42101; 270-745-4156
nightsky photo of Sagittarius and Windmill
from Chews Ridge, near Carmel, in California. This is a 20 second exposure,
f/1.7, 400 ASA color slide film, taken using a cable release with a single
reflex lens camera on a tripod. (Vivian Hoette)
your own pictures. See Explorations, Storms and Stars, for
So your students become familiar with telescopes, gather pictures of
telescopes or arrange for an amateur astronomer to bring a telescope to
class. Best yet, arrange for a Star Party with the help of your local
amateur astronomy club or planetarium.
Time: approximately 30 - 40 min.
Prior to this activity, have each student bring in a picture of a telescope. Students should record any information
that is readily available about their scope.
The student page for this activity has links to telescope pictures. You
may wish to have students view these pages instead of or in addition to
collecting pictures of telescopes.
by displaying any picture of the night sky. Tell the students that in this picture there is a small
cluster of stars that they have been asked to investigate. You may point to any starry or fuzzy
area on the picture or even a blank spot, claiming that as the location of
the cluster in question.
Why is investigating this star cluster
going to be difficult? Challenge the students to think about this
problem. The cluster of stars
may appear small and dim to us. Do
we know it is small? It might
be very big. Is it really dim, or just far away?
- Ask: What is the primary tool that astronomers
have available to them to overcome the problems of distance and dimness? Most students will know that astronomers
use telescopes. If students gathered pictures of
telescopes for home, they can Student homework was to gather pictures of
telescopes. Since it is difficult to see parts of scopes from pictures
if you have no actual experience with real telescopes, the best option is to
have actual telescopes available to view.
students to share the telescope pictures they gathered for homework or share
the notes they made about telescopes they viewed on the web pages linked to
the Student Page. Ask: Do all
these telescopes look the same? What
do all these telescopes seem to have in common? List parts: mirrors, lenses, tubes, mount,
tripod or base of some sort etc. Record all responses on the board, an
overhead or on butcher paper.
- Ask: Telescopes can look very different but
what are the things that astronomers want all telescopes to do? Students may recognize that
telescopes need to make things look brighter, bigger, and show detail
clearly. However, they may not
understand how the the parts of telescope systems work together to
accomplish these goals. Record all responses. Try for some degree of agreement
among the group as to what will be put on the list.
question: Why do you think there are so many
different telescopes? Students might consider the different observing
projects or different science objectives or different budgets or available
technologies that would lead to the building of different kinds of
to the students that they will be doing a series of investigations that will
allow them to explore the different properties of
telescopes. They will be learn how the properties of a telescope
and the CCD imaging system affects images produced by that telescope.
The activities should provide for students a basic understanding about what
kind of telescope would be most useful for imaging a particular target or
for conducting an observing research project.
This activity is designed to stimulate interest in the technology of
telescopes and to help you assess the level of prior knowledge of the class as a