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The School of Galactic
Radio Astronomy:
An Internet Classroom
M. W. Castelaz, J. D. Cline, C. S. Osborne
(Pisgah Astronomical Research Institute)
D. A. Moffett (Furman University)
J. Case (Brevard High School)
199th Meeting of the AAS, Session 23.15, 7 January 2002
Introduction
 The purpose of SGRA is to teach the basics
of scientific inquiry, which includes
methodology, critical thinking, and
communication of results to students in
grades 8-12.
 Reinforces student use of math, physics,
chemistry, technology, and computer
science.
 Relies on Internet access to PARI’s remotecontrolled 4.6-m radio telescope.
The Curriculum
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Consists of modules arranged by topic and by type
of celestial object.
Each module contains the following sections:
Introduction, Observations, Results, and
Discussion.
The modules vary in difficulty and depth giving
teachers flexibility in their classroom instruction.
All of the SGRA curriculum modules address
content, teaching, professional development, and
program standards.
All modules use the PARI 4.6-m radio telescope.
Module Title
Module
by Topic
Topic
What’s Between
the Stars?
Radio emission from interstellar clouds
Detecting Radio
Waves
How radio telescopes and their detectors work
Radio Waves
from Space
How different type of radio emission are produced
Mapping
Constructing a contour map; a Math exercise
Waves and
Energy
Concept of energy per second emitted by a radio
source
Module Title
Module
by
Celestial
Object
Celestial Object
What Does the Center of the
Milky Way Look Like?
Galactic Center
Star Formation, Interstellar
Dust, and Gas
Orion Nebula
Collapsed Stars
Pulsars
Expanding Shell of Matter
Cassiopeia A
Close to Home
Moon and Sun
* Description of the Curriculum Modules *
“What’s Between the Stars?”
Students are familiar with the visible night sky. The goal of this module is to expand
their vision of the night sky. The introduction to the lab includes a description of
visible images of the center of the Milky Way Galaxy, or the Orion Nebula. The
students will download the images from the SGRA website. The observations, using
the PARI 4.6-m radio telescope, will consist of mapping 21-cm emission from either
the center of the Milky Way or Orion. Results will be a comparison of the visible and
radio maps, and a discussion of the difference.
“Detecting Radio Waves “
The goal of this module is to introduce students to the technology of antennae and
receivers, and the basics of telescopes. The introduction to the module is a
description of electromagnetic waves (e.g. wavelengths, frequencies, speed of
light), and how an antenna detects an EM wave. The introduction also describes
telescopes as light gathering instruments that can resolve small angular sizes.
Observations will be made of several radio bright celestial objects, producing maps.
Results and discussion will emphasize the detection of the radio waves over vast
distances.
“Radio Waves from Space”
Similar to visible light, radio waves from celestial objects can be observed in
emission, absorption, or as a continuum. The introduction to this module describes
the mechanisms for the production of the radio waves. Observations will be
spectra of a radio emission line object, an absorption line object, and a continuum
source. This module is different from the others in that it measures spectra, rather
than mapping the spatial extent of an object. Spectroscopy may be most
appropriate for the upper grades. Results and discussion concentrate on
interpreting the observations in terms of the different types of radio wave radiation.
“Mapping”
The goal of this module is to develop mapping and graphing skills, which are important in
scientific inquiry. After an introduction on the concept of contour maps, students will set
out to observe a radio source (e.g. Orion Nebula). They will sample the brightness of the
source at regular spatial intervals over the area of the object. Without the use of a
computer, the students will work together plotting the intensities by hand, developing a
contour map. Results and discussion center on the contour map that was produced and
how well it represents the actual object.
“Waves and Energy”
Radio waves carry energy, and also represent the amount of energy in the source of radio
waves. The goal of this module is to have the students understand how much energy
some of the celestial radio objects emit. The students will measure the overall 21-cm
brightness of a celestial object. Results will use their measurement, and some given
properties (such as distance) to calculate the amount of energy emitted by the object they
observed. Discussion will compare that energy to the Sun, and their own local electric
company generators!
“What Does the Center of the Milky Way Look Like?”
The goal is to compare a 21-cm radio map of the center of the Milky Way to visible images,
emphasizing the striking differences in visible absorption and radio emission of
electromagnetic radiation. Observations at 21-cm include mapping the Galaxy’s center, and
downloading visible images from the SGRA website. Results and discussion center on the
differences in 21-cm and visible maps.
“Star Formation, Interstellar Dust, and Gas”
The goal of this module is to teach students about the existence of gases and dust in the
interstellar medium, and in particular in regions of star formation. The introduction includes
visible images of the Orion Nebula and star formation theories. The students will make a 21cm map of the Orion Nebula to compare with the visible images. Results and discussion will
emphasize the extent of the gases and dust, and the importance in the formation of stars.
“Collapsed Stars”
The goal of this module is the study of the last stages of a star’s existence. Students
will be introduced to pulsars. The flux from pulsars is low at frequencies that can be
measured with the 4.6-m radio telescope. So, data from the PARI pulsar timing
project, measuring the flux from pulsars at 400 MHz using one of the PARI 26-m radio
telescopes, will be made available for students to download. This is the only module
that does not include direct observation with the 4.6-m radio telescope. Results and
discussion will center on the mechanism that can produce fairly regular millisecond to
second pulses from a celestial object.
“Expanding Shell of Matter”
The goal of this module is to measure the extent of a supernova remnant, and the
energy needed to produce it. Students will map Cas A, one of the brightest radio
sources in the sky, at 21-cm. They will compare the radio map to visible images, and
the discussion will include the reasons for the differences.
“Close to Home”
The sun and the Earth’s moon are bright at radio frequencies. Students are familiar
with both the sun and moon in the visible. The students will make a 21-cm radio maps
of sun and moon. Results and discussion will show how such a familiar object can
appear in the radio part of the spectrum.
The 4.6-m Radio Telescope
“Smiley”
South Carolina State University
faculty and students, and
PARI staff at the 4.6-m radio
telescope. SCSU PAIR
Program concentrating on 4
technical aspects of
“Smiley”.
SCSU is developing
1. Computer Control
2. Web Interface
3. Feed and Receiver
Temperature Control
4. Database
* Computer Control *
Visual Basic 6 GUI
developed thus far, in
house, for ease of use
4 Ways to Point:
• Click on map and GO
• Click on Object in Menu and GO
• Enter Equatorial or Horizon coordinates
• Manually with Handpaddle
Track or Drift Mode are available;
Map shows where telescope points at all times, and desired position.
* Feeds and Detectors *
1420 MHz, 4.8 GHz, 6.67 GHz, 12.2 GHz Feeds and their
spectrometers are controlled by VB6 software interface
Record either continuum or
spectrum (up to 4 MHz
bandwidth)
4.8 GHz Drift Scan
ContinuumMap of
SNR 049
Teacher Workshops and Use
* Workshops *
For a teacher and class to participate in SGRA, the teacher
needs to attend a 2 day workshop. Goals of the workshop:
• Learn how to use the 4.6-m radio telescope on site and
remotely;
• Learn the basics of radio astronomy;
• Develop proficiency in using the curriculum modules;
• Develop one original use of the SGRA facilities.
Two workshops planned for Summer 2002, and 2 each
term during the academic year.
Accommodate 10 teachers per workshop.
* Use *
To use the 4.6-m radio telescope:
• Teachers schedule time at workshop;
• Teachers logon at their scheduled time;
• Webcam and Website of Smiley is accessible by
anyone on Internet, but control is done solely by
teacher logged in.
• WebSite has four parts:
• Radio Astronomy Basics
• Control Room (accessed by teacher logged in)
• Guide Books
• Log Book
•
Radio Astronomy Basics: Includes concepts of
electromagnetic waves, detection of electromagnetic
waves, sources of astronomical radio waves, how
astronomers use radio telescopes, and several simple,
relatively inexpensive experiments teachers and
students can perform.
•
Observing: The link to controlling the radio telescope
and making the measurements of 21-cm radiation.
Controls include options of source selection,
coordinate entry, slew, set, and guide selection, and
tracking. We will use free software called Virtual
Network Computing (VNC found at
http://www.uk.research.att.com/vnc/) to allow access
to the telescope controls over the Internet.
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Guides: contains atlases of the astronomical sky,
catalogs, examples of observing sessions, guidebooks for
data reduction, and data reduction software that can be
downloaded for analysis offline.
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Logbook: primarily a guestbook, but we will request
comments pertaining to use of the facility. The
Logbook is one of our sources for evaluation of the
project.
Timeline
2001-2002
• Development of the Interactive Internet use;
• Begin interaction in Spring 2002 with one or
more local schools to study effectiveness and
make appropriate adjustments to the program
2002-2003
• Offer 2 workshops for area teachers during
Summer 2002
• Begin first full year of operation Fall 2002
Acknowledgements
We acknowledge the Space Telescope Science Institute
IDEAS Program for partial support of the School of
Galactic Radio Astronomy.
Also, we appreciate the support we have received from
the South Carolina State University NASA PAIR program
for their development of the 4.6-m radio telescope
controls and detectors. This is a mutual benefit between
the SCSU students and mentors and PARI.
We also acknowledge support from the Z.Smith Reynolds
Foundation for their generous support of teacher
workshops.
Contact Information:
A not-for-profit public foundation
Michael Castelaz
Astronomical Studies and Education
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC 28772
Phone: 828-862-5554
FAX: 828-862-5877
E-mail: [email protected]
Web: http://www.pari.edu