The 3 Metre Radio Telescope

The Radio Meteor Detector

Other Radio Projects

This is our radio astronomy page. At Bathurst Observatory, we have installed a 3 metre radio telescope that is used as an introductory device  to learning about radio astronomy for schools and interested groups. We have also installed a radio meteor detector. The latest change will be a new USB model winradio receiver that will be added to our system, likely late in 2008, to replace our current winradio model. The Bad News at present is that the old computer with the winradio card installed in it has been pensioned off. The older model of the winradio card is not compatible with the newer computers, so unfortunately, all radio astronomy work is limited until we can come up with the money to buy a new USB model of the winradio system. We are still doing on demand work with the radio telescope having revived the old computer.

The 3 metre and 1.5 metre Radio Telescopes

The 3 metre dish is operational when needed, operated via the old computer system. Below is a list of the things it is capable of doing.   The dish will primarily be used for listening for signals coming from hydrogen gas in the milky way and for solar work. 

At present, we can use our 3 metre radio telescope for scans of the sun at 4000 MHz. An example of such a scan can be seen below. We have now detected the hydrogen line at 1420 MHz using our 3 metre dish and specially built receiver.  We have also mounted the meteor detector inside the 3 dish, to remove ground reflections.

Above, the sun on the 18th of April 2003 using the 3 metre dish.

We have also installed a smaller 1.5 metre dish, that we use to scan the sun at 12 GHz. It is fully movable so sun scans can be done at any time of the day. We are about to start a small research project using this dish on the sun. We are also experimenting with lower frequency sun detection. 

The Radio Meteor Detector

The radio meteor detector is fully functional, but again now in on demand use via the old computer. We have written a number of papers detailing results of this counter, copies of which may be obtained by contacting us. 

How does the counter work?

Meteors or “Shooting Stars” are small fragments of rock from within our solar system that burn up in Earth’s atmosphere when they fall to Earth. Meteors typically burn up some 100 km up in Earth’s atmosphere. If they are large enough to hit the ground, we know them as meteorites. Most of the meteors you see, however, are rocks no bigger than a pea in size.

 So how does our counter work? We have constructed a special aerial called a cross dipole and located it near the observatory. It is now actually located in the 3 metre dish. This aerial is used to detect meteors burning up in Earth’s atmosphere. We also have a special receiver tuned to a very distant FM transmitter (Up to 800 km away). Normally, you cannot pick up a signal from such a distant FM transmitter here in Bathurst, but when a meteor enters our atmosphere and burns up, it produces a trail of ions behind it. The ions produced act like a big reflector for radio signals and we can hear the distant transmitter signal as a “ping” sound in our detector. It also produces a spike on our signal graph, which we can record.

 The meteor counter and radio telescope would not have been possible without the assistance of Winradio, Sky, Bob Murray from Murgon Aerials, Steve’s Electronics (particularly Dave Scott), Members of the Centaurus Astronomy Society, and Prof David McKinnon from CSU.  

As mentioned earlier, Prof David McKinnon in conjunction with the observatory have also just written a number of papers on the results from the meteor detector. 

The graph above was produced by a Leonid meteor on the 16th of November 2002. We also recorded many more during the peak activity on the 19th of November.

With the move from analogue to digital television fast approaching, we are investigating other transmitters that we may be able to use once the analogue ones are switched off, sometime in the next few years. So at present, we are planning to undertake an investigation into other suitable frequencies.

Weather Satellites

We have also found that the winradio card in our pc and one of our antennas, is particularly good at picking up weather satellites. We can receive Noaa and meteor weather satellites. In particular are Noaa 17 (137.620 MHz) and Noaa 12 (137.500 MHz) and now the new satellite Noaa 18 (137.91 MHz),  which give us great pictures. We use a computer program  to decode the pictures and display them on our computer. We hope to again do these if we can afford one of the new systems.

Other Radio Projects

This section will detail other projects in addition to those listed above.  

We also can listen to astronauts onboard the International Space Station (ISS). These broadcasts are generally at 145.8 MHz and the astronauts can be clearly heard talking to amateurs radio operators.