General Comments on Radio Astronomy

To the uninitiated, radio astronomy is usually associated with giant parabolic dishes listening for ET to broadcast some cryptic transcendental number. Of course, this is not what radio astronomy is all about. The light of stars and galaxies span the entire electromagnetic spectrum: gamma/x-ray, UV, visible light, IR, microwave, and radio waves. When analyzed in concert, this light tells us much about them. Detectors, telescopes, and antennas are the sensors whose names are sometimes confusingly interchanged.

Karl Jansky discovered extraterrestrial signals in 1932. Grote Reber followed up his work and identified that the radio emissions came from the center of our galaxy. Radio Astronomy was born. We now know that the strong radio signature is articulated by a super massive black hole in Sagittarius.

The invention of the transistor, with its impact on telecommunications and radar, no doubt contributed to the development radio astronomy as a viable field of experimental research. Similarly, what was once reserved for professionals, due to challenging concepts and large expensive electronic systems, is now accessible to many amateurs with different levels of skill. One dinosaur, the 4 GHz C-band satellite dish that once "roamed" our country backyards, has been affordably retrofitted with special amplifiers for sentinel duty. Over a dozen galactic targets drift into view of the antenna beam and are noticeably recorded.

But we can also look in our own solar system for radio sources. The signals may be so strong and in the right end of the radio spectrum that only very inexpensive equipment is needed. Raging solar storms or Jovian electrodynamics produce intense radio waves in the decametric range that can sneak through our ionosphere (15-40 MHz). Direct conversion of these radio waves to audio renders these broadcasts as roars, chirps, and crashing waves.

It is with simple electronics and a variety of simple antennas, such as a single 25-ft dipole, that the research below embraces. A new dimension of utility, a new probe for physics, a new quest for adventure for the amateur radio astronomer is undertaken with these basic designs.

Below are several sites that are excellent platforms from which to launch from for a more dedicated study as well as providing basic background terminology:

Society for Amateur Radio Astronomers (SARA)

NASA Project Radio Jove

Radio Astronomy and Amateur Radio

Windows to the Universe

SEC Glossary of Solar-Terrestrial Terms

20 MHz Radio Astronomy: Resources for Comparative Studies

At the SARA 2003 Conference, I discussed some aspects of solar physics with a 20 MHz antenna. There is a spirited effort underway at the Tamke-Allen Observatory (TAO), owned by Roane State Community College in Harriman, TN, to correlate decametric emissions among different locations, receivers, and antennas. Captured solar bursts are compared with Optical, UV, and X-ray instrumentation signals. Laboratory satellites like Solar Heliospheric Observatory (SOHO), which orbits around the Lagrange point L1 and the solar x-ray imager aboard the Geostationary Operational Environmental Satellite (GOES) in geosynchronous orbit, collect these data and, by telemetry, send it to ground based computers.

SOLAR DATA RESOURCES

(1) A compilation of useful SOHO and GEOS satellite data are found at "Solar Physics on the Web." Below is a solar storm and geomagnetic storm monitor from the site and a link to it which shows current x-ray and particle flux as well as other data like magnetometer readings.

Solar X-rays: Geomagnetic Field:

>

From Solar X-ray & Geomagnetic Storm Monitor

(2) A comprehensive listing of NASA space-borne laboratories (ACE, Cluster, FAST, IMAGE, Polar, RHESSI, SAMPEX, SOHO, TIMED, TRACE, Ulysses, Voyager, and Wind) is extractable from the Sun-Earth Connection Data Availability Catalog Mission Overview Matrix. This is an extremely useful table and links to project descriptions and to live and archived data.

SECDAC Mission Overview Matrix

A useful item in the matrix is the link to various homepages and mission matrices for each of the above. These in turn have links to real-time data as well as to archived data. For example,



(3a) Follow the links to the WIND spacecraft/WAVES instrument package/Waves homepage for electronic data products. Useful spectrograms of 20-14,000 KHz radio emissions are available from 1994 as well a a listing of Type II & IV solar burst events:

WIND Daily Spectrogram Plots and Type II & IV Solar Burst Lists

(3b) ACE Interplanetary Magnetic Field data archives (from 1997 to present)

IMF Data

(4) Follow the links from the overview matrix to, say, SOHO/GONG/. It will show all the available SOHO data:

SOHO Data

Choose

Near Real Time Images and Movies, which features 3 of the 12 SOHO instruments:

EIT (Extreme UV Imaging Telescope)
MDI (Michelson-Doppler Imager) Continuum and Magnetogram
LASCO (Low Angle and Spectrometric Coronograph Experiment)

(4a) The latest solar images with these instruments are found on

The Sun Now

(4b) From the SOHO Data page, choose the specific instruments under "Other Near Real Time Data," which represent other instruments aboard SOHO:

-VIRGO (Variability of Solar Irradiance and Gravity Oscillations)
-Total Solar Irradiance
-CELIAS (Charge, Element and Isotope Analysis System)
-Proton and Energetic Particle Flare Activity Monitors, X-ray Flare Monitor
-ERNE (Energetic and Relativistic Nuclei and Electron) Proton and Helium Intensity
-MDI Far Side Imaging
-SWAN ((Solar Wind Anisotropies) Far Side Imaging

For a decription of the 12 SOHO Instruments, see the link below:

SOHO Instruments

(4c) SOHO Data page also has the "Other Near Real Time Data" list, which has the particularly useful "Solar/Heliospheric Forecast" and "Recent Solar Activity" subheadings.

(5) Solar/Heliospheric Forecast has many good products including Solar wind model and Virtual Star Lab:

Solar & Heliospheric Weather Model (IMSAL)

(6) From here, the Solar Data link is Solar Physics on the Web, which has comprehensive live and easy-to-use archive database (SOHO, GOES, WIND and the MEES Solar Observatory in Hawaii). Recommend to have some of these open when collecting Radio Jove data.

Solar Physics on the Web

(7) Recent Solar Activity: pinpoint the sunspot group that was active.

Choose an event in the time span given, perhaps the strongest X-ray flare (in order of increasing intensity: A, B, C, M, X)

Solarsoft (Lockheed Martin Solar and Astrophysics Laboratory) displays:

Header Information: Event Number, GOES Flare Classification, etc.

Flare sequence images (JavaScript frames w/ GOES flux plotted above)

TRACE event sequences 171A images (JavaScript, GIF Animations, or MPEGs), and

Flare locator image

Latest Solar Events

(8) Archived data (item 7) is harder to come by. Solarsoft is developing access to the database. However, the GOES data is easily retrievable back to 1991 from their Yohkoh solar x-ray telescope database:

Yohkoh GOES Data Base Browser

(9) IPS Radio and Space Services provides seceral excellent resources under their "Space Weather" and "Solar" links. Real time Coolgura (18-1800 MHz) and Learmonth (25-180 MHz) Spectrograms as well as daily historical data up to 3 months (Coolgora). Space weather and ionospheric data is also provided.

Australian Space Weather Agency

(10) Space Weather, current and archived data. Also has good links to basic solar physics.

Informationabout the Sun-Earth Environment

COMPLEMENTARY RESOURCES

An assortment of specialized resources helpful in the study of solar burst (and Jovian storm) time series data (Project Radio Jove are included in this section. The list is far from exhaustive, but has been useful for my pursuits. Some emphasis is towards both real-time and archived data that will aid in the study of ionospheric and meteorological conditions.

(1) A series of graduate level lectures on plasma physics: International Max Planck Research School on Physical Processes in the Solar System and Beyond at the Universities of Göttingen and Braunschweig.

Solar System School

(2) Ground based facilities, like the Alaskan High Frequency Active Auroral Research Program (HAARP). Ionospheric data (real time and archived) is available under the various instruments (Magnetometer, Riometer, HF Ionosound, Total Electron Content, Spectrum Monotor, etc.). See "Scientific Data from the Site" in the Table of Contents below,

HAARP Table of Contents

(3) Services, like those of Northwest Research Associates (NWRA) Space Weather and Ionospheric Scintillation Predictions. Very helpful staff. Site has good links to tutorials.

Space Weather Services

Ionospheric Scintillation Predictions

(4) Products from several weather and lightning satellite databases. For example, aviation weather products may be more helpful than a generic wether report or forecast. Sky conditions and upper level winds could be helpful in assessing tropospheric effects on radioastronomy. The link to weather does require some familiarity with aviation terminology. Similarly, lighting data may shed some light on both tropospheric and stratospheric lightning which could impact analysis of radio astronomy signals. A current US Lightning Map is available as a free download (requires registration). Archived data is available for a fee.

Aviation Digital Data Service

Vaisala Lightning Explorer

(5) Projects like the GLOBE Program, a worldwide hands-on, primary and secondary school-based education and science program, can useful to the amateur radio astronomer. It allows comparison of certain conditions during coordinated observing. Some climatological data to be displayed on a 3-dimesional globe that one can manipulate (a good option but may require a free software download). Be sure to choose some reference data, like satellite and model, select the day, month, and year (to 1995):

The GLOBE Program

Images provided by Weather Services International Corp. (WSI) and NASA though the Global Energy and Water Cycle Experiment Continental-Scale International Project.

Currently Available
1 April 1995 to 18 April 1997, Daily
19 April 1997 to 29 May 2004, Hourly

Select the Radar product in the link below:

NEXRAD Archived Radar

(6) Specialized Databases like the 81.5 MHz Interplanetary Scintillation. Some animations are available for 1990-1993.

Interplanetary Scintillation (IPS) Data

IPS Hammer-Aitoff Projection March 1992

(7) Prediction of Jupiter storms is based on the interaction of the Jovian moon, Io, with the Jovian magnetic field. Professor Kazumasa Imai (Kochi National College of Technology, Department of Electrical Engineering) has prepared a useful prediction tool. This will prove invaluable to assess the potential influence of certain Jovian storms occurring concurrently with a solar burst (this speculation will be defended later).

The Jovian Daily Ephemeris

(8) Solar and Jovian data files from October 1999 (mostly decametric) can be accessed via the link on the Radio Jove homepage (above). It can be directly accesed via "View Current Data Archive," which allows one to specify the fields to view (be sure to mark "Data Products").

Radio Jove Data Archive

(9) Other than to look at picture files of the signal traces in the archive, one will need the SPD wave files to manipulate the data. Radio Sky Publishing has free PC software that allows strip chart recording and sharing files over the internet. The affordable Pro version may be required for som features, like converting the SPD files to TEXT files which can be manipulated in EXCEL.

Radio Sky Publishing/SkyPipe Software

(10) Planetarium software is helpful in seeing the astronomical landscape at various observing sites in the comparison study. There are many good ones available. Some come free with the purchase of astronomy textbooks. Starry Night is cross platform friendly and is worth checking out. It is available for a free 15-day trial:

Starry Night Planetarium Software

A free Windows-based (Windows 95/98/NT/2000/XP) program to draw sky charts with the capability to superimpose images (like a radio target on an optical field) can be downloaded from the link below.

Cartes du Ciel (Sky Charts)

A good resource for planetarium software that is available for different platforms is tabulated by SEDS:

Planetarium Software List

(11) Geographical Information is obtained from several databases when the planetarium software falls short:

USGS Geographic Names Information System

Topographical Maps & Coordinates (Topozone)

Maporama: Lat/Lon for Specific Location

(12) Astronomical information

Greenwich Sidereal Time Calculator (Astro Java)

(13) Geomagnetic Latitude and Longitude

Convert Geographic to Geomagnetic Coordinates

Sunspot Data (ASCII)

Virtual Observatory

Sloan Digital Sky Survey/Skyserver

Teaching Astronomy with the Sloan Digital Sky Survey Data (8 MB ppt)

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