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

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 remote-controlled 4.6-m radio telescope.

Introduction

The Curriculum• 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 by

Celestial Object

Module Title 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

Module Title

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 by

Topic

* 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.

“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 21-cm 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.

“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!

“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.

“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.

The 4.6-m Radio TelescopeSouth 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 Control2. Web Interface3. Feed and Receiver

Temperature Control4. Database

“Smiley”

4 Ways to Point:• Click on map and GO• Click on Object in Menu and GO• Enter Equatorial or Horizon coordinates• Manually with Handpaddle

Visual Basic 6 GUI developed thus far, in house, for ease of use

Track or Drift Mode are available;Map shows where telescope points at all times, and desired position.

* Computer Control *

* 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

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.

* Workshops *

* 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.

• 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.

• 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.

 

Timeline2001-2002 • 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:

Michael CastelazAstronomical Studies and EducationPisgah Astronomical Research Institute1 PARI DriveRosman, NC 28772

Phone: 828-862-5554FAX: 828-862-5877

E-mail: mcastelaz@pari.eduWeb: http://www.pari.edu

A not-for-profit public foundation