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NASSP and Rhodes University Students Radio Astronomy Practical 2006/09/11-18


Students of South Africa's National Astrophysics and Space Science Programme arrived at HartRAO on 2006 September 11 to start their radio astronomy practical. A total of sixteen NASSP students participated - Renee Hlozek, Chigomezyo Ngwira, Edward Bernhardi, Masimba Paradza, Bosco Oruru, Fred-Joe Nambala, Rupert Spann, Yabebal Fantaye, Donald Mashigo, Daniel Cunnama, Faith Hungwe, Jean Uwamahoro, James Mason, Daniel Wium, Andrew Mori and Kritesh Harpaul.

They were joined by three Honours students from Rhodes University Department of Physics and Electronics - Greg Atkinson, James Barry and Steven Liddell.

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Sarah Buchner was on hand to meet the students when they arrived, and started the practical the next day. The first experiment was to use a hand-held satellite dish to detect the Sun, and make an estimate of its brightness temperature.

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Mike Gaylard introduced the students to the calibration of the 26-m radio telescope, using the radio sources Hydra A and Virgo A. The next day the students predicted which planets might be detectable with the radio telescope, and Jupiter was picked as a suitable target for measurements in four wavelengths bands. Drift scans were made across the planet, and these enabled its radio spectrum to be plotted and compared to that expected for a solid object of "known" temperature.

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The students were introduced to the space geodesy research programme at HartRAO as well as to the radio astronomy. Here Attie Combrinck, in the orange shirt, describes the use of Global Navigation Satellite Systems for scientific purposes such measuring tectonic plate motion and the atmospheric water vapour content.

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The 26-m radio telescope seen in the background spends more than 50 days each operating in global networks of radio telescopes for the purpose of studying the Earth paremeters including its rotation and orientation in space. Here Attie Combrinck describes these geodetic VLBI experiments to the students.

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The radio telescope provides an appropriate backdrop for a group photograph.

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Prof. Justin Jonas from Rhodes University prepares the students for the microwave practical in which they will measure the noise figure of a receiver system.

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Justin Jonas fills the cold load with liquid nitrogen, in preparation for determining the receiver temperature using the hot/cold load method.

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Measurements of the microwave receiver temperature get under way.

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Justin Jonas took the students up the telescope so they could inspect the instrument they were using. Here Justin, on the right in the pale blue shirt, discusses the 18cm wavelength receiver, which is mounted externally to the central Cassegrain housing the other receivers.

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The students get a feel for the size and height of the telescope.

Sarah helped the students to spend their Saturday usefully, investigating pulsars and in turn using them to investigate the interstellar medium.

Mike returned on Sunday to introduce radio spectroscopy; the students obtained the spectrum of a radio recombination line from the well known HII region the Omega nebula. Combined with a measurement of the continuum antenna temperature via a drift scan across the nebula, they can then determine its temperature.



created 2006/09/14 by Mike Gaylard.