Radio telescope tour

June 15

The Socceroos have a day off and so no media availability. I went on a fascinating tour of the Hartebeesthoek Radio Astronomy Observatory, about 30 minutes from Apricot Hill. The original 26-meter antenna was built by NASA to track satellites, especially the early lunar probes. It’s in an ideal location, high altitude, dry climate and outside the tropical zones of the Earth. It’s used now for various astronomical research and also as a type of GPS with other radio telescopes to accurately detect movement of the continents.

I missed the monthly Saturday public tour so I emailed their Science Awareness Programme and actually got a reply. So Marion West, one of the resident astronomers, agreed to give me a private tour. Her specialty is the shell of expanding gas around an exploded star, something that will happen in “5,000 million years” she says.

The Hart RAO is a fairly basic facility in a relatively quiet area northwest of Johannesburg. The centerpiece is the big 26-meter antenna and there are several smaller antenna, all doing ‘radio’ astronomy- looking at objects in the sky by detecting their radio wave emissions. So they can do observing 24 hours a day, since light and usually weather doesn’t affect their observing.

But many things do affect the telescopes, mainly anything that emits any kind of frequency, like cell phones and microwaves. So they can’t have any of those at the site. Marion said often a car starting up can cause a ‘glitch’ in their data. The creeping suburban sprawl of Johannesburg will have an effect in a few years, the astronomers say.

Marion rummaged around in a storage room of educational things and found a small dish antenna, an electronic box, a lamp and extension cord. So we took all of this outside where she demonstrated how various items emit radiation in the form of radio waves. It was fairly low tech but effective. A school group happened to be there at the same time, they have a pretty big visitor center with all sorts of hands-on displays.

In the control room for the big telescope, she showed me the various instruments that looked like they were out of an old NASA film of the 60’s space program. Marion explained they did date from the 60’s when NASA built the telescope. Finding parts is difficult, tiny pens for the graph paper and real bulbs for the control panel lights.