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31 January 2023 | Story Leonie Bolleurs | Photo Leonie Bolleurs
UFS unveiled new spectrograph
Assisting Prof Richard Gray with the installation of the spectrograph and the polarimeter were the Electronics and Instrumentation departments at both the UFS and the ASU. Left from the spectrograph, are from the left, front: Innes Basson, Head of the Department of Electronics and Instrumentation, Prof Pieter Meintjes, Senior Professor in the Department of Physics, Mark Jackson, Department of Electronics and Instrumentation, Hélène Szegedi, Lecturer in the Department of Physics, and Prof Richard Gray. At the right, from the spectrograph, front, are Natali Matchelt, master’s student, Izak van der Westhuizen, Lecturer in the Department of Physics; Barend Crous, Department of Electronics and Instrumentation; middle: Wian Smit, master’s student, Joleen Barnard, master’s student; back: Kobus Krüger, Department of Electronics and Instrumentation, Henri Roodt, Department of Electronics and Instrumentation; and Dr Hendrik van Heerden, Department of Physics.

The University of the Free State (UFS) is gearing up to be a leading academic institution in astronomical research. The institution successfully mounted a spectrograph with a polarimeter to the Boyden Observatory 1,5-m telescope that will provide scientists with visual access to both the Northern and Southern Hemispheres. 

The instrument, which can be accessed from Boyden, an astronomical research observatory and science education centre a few kilometres outside Bloemfontein, will allow researchers such as the Astrophysics Group at the UFS to do simultaneous polarimetry and spectroscopy of astronomical sources. This is vital for the research they are working on.

Mounting the spectrograph to the telescope and installing the polarimeter completed the upgrade of the 1,5-m telescope and is a leap forward for the astrophysics group at the UFS. The upgraded telescope with the spectropolarimeter, with a valued cost of R1.5 million, will also provide unique opportunities for collaborative research between the Astrophysics Groups at the UFS and researchers from the Appalachian State University (ASU). This adds greatly to the astrophysics research capacity at the university.
 
Prof Richard Gray, who 2019 started with the development of the astronomical spectrograph for the UFS Department of Physics, is a world-renowned expert in stellar spectroscopy, from the Department of Physics and Astronomy at ASU in North Carolina in the US. He was mainly responsible for the development and building of the instrument. 

Prof Pieter Meintjes, Senior Professor from the UFS Department of Physics, describes the moment that installation was completed as a feeling of enormous relief. “It took many hours of hard work, planning and testing to marry the 90-year 1,5-m telescope with the new sophisticated instrument,” he says. 

Adding value to graduate programme

Besides the development and installation of the spectrograph, Prof Gray also designed and built a polarimeter which can be integrated with the spectrograph. When placed inside the spectrograph, this piece of equipment transforms the spectrograph into a spectropolarimeter, giving it additional functionality. “This allows us, for example, to detect and analyse polarised light. It enables us to study the effect of magnetic fields in astronomical sources which introduce various polarisation signatures that can be detected with the polarimeter,” explains Prof Gray.

“I am fascinated by the polarimetric capabilities that we never had before. It is a great step forward,” remarks Prof Meintjes. 

“The Department of Electronics and Instrumentation at the UFS played an enormous role in the building of several components of the instrument that Prof Gray designed, as well as getting the 1.5-m telescope research ready so that the completed instrument could be mounted to the telescope”, says Prof Meintjes

He envisages that the research instrument will be ready for research purposes by March this year. Up till then researchers, graduates, and third-year students will have the opportunity to spend time on the spectrograph to familiarise themselves with it.

polarimeter
Prof Richard Gray posing with the polarimeter. With him is Prof Pieter Meintjes. (Photo: Leonie Bolleurs)


“Once installation is finalised, the UFS will be the only academic institution in South Africa with access to a 1.5-m telescope paired with a spectrograph. This gives us an edge in terms of our astrophysics programme and the training we provide our students. It also adds so much value to our graduate programme,” he says.

New instrument provides much flexibility

The spectrograph offers Prof Meintjes many possibilities for his research, and he is eager to put the instrument to use. To study binary systems as well as the jets of Active Galactic Nuclei (AGN), you need a spectrograph, preferably with polarimetric capabilities. It can also be applied to finding elements at the surface levels of stars so that their chemical composition can be determined.

“In the past, we needed to send our researchers to Sutherland and they were never guaranteed clear skies. Having this facility gives us so much flexibility,” he says.

 

Tsebo Matsoso and Siphephelo Ndlovu

Prof Brian van Soelen from the Department of Physics will be a key user of the spectrograph for his research. He is also playing an important role in terms of postgraduate training and research where the spectrograph is applied. 

Photo: Mart-Mari Duvenhage

  

 


The polarimeter converts the spectrograph to a spectropolarimeter. This instrument, which is mounted on a telescope (in the case of the UFS, it is mounted on the Boyden 1,5-m telescope) enables the user to detect whether radiation from  astronomical objects are polarised and to analyse the level of polarisation of the  light. Scientists can then, for instance, study the effect of magnetic fields in astronomical sources, which introduce various polarisation signatures (typically with a characteristic  level of polarisation).

News Archive

Research into veld fires in grassland can now help with scientifically-grounded evidence
2015-04-10

While cattle and game farmers are rejoicing in the recent rains which large areas of the country received in the past growing season, an expert from the University of the Free State’s Department of Animal, Wildlife, and Grassland Sciences, says that much of the highly inflammable material now available could lead to large-scale veld fires this coming winter.

Prof Hennie Snyman, professor and  researcher in the Department of Animal, Wildlife, and Grassland Sciences, warns that cattle and game farmers should be aware, in good time, of this problem which is about to rear its head. He proposes that farmers must burn firebreaks as a precaution.

At present, Prof Snyman focuses his research on the impact of fire and burning on the functioning of the grassland ecosystem, especially in the drier grassland regions.

He says the impact of fire on the functioning of ecosystems in the ‘sour’ grassland areas of Southern Africa (which includes Kwazulu-Natal, Limpopo, Mpumalanga, the Eastern Cape, and the Harrismith environs) is already well established, but less information  is available for ‘sweet’ semi-arid grassland areas. According to Prof Snyman, there is no reason to burn grassland in this semi-arid area. Grazing by animals can be effectively used because of the high quality material without having to burn it off. In the sourer pasturage, fire may well form part of the functioning of the grassland ecosystem in view of the fact that a quality problem might develop after which the grass must rejuvenate by letting it burn.

Prof Snyman, who has already been busy with the research for ten years, says quantified data on the impact of fire on the soil and plants were not available previously for the semi-arid grassland areas. Fires start frequently because of lightning, carelessness, freak accidents, or damaged power lines, and farmers must be recompensed for this damage.

The shortage of proper research on the impact of fires on soil and plants has led to burnt areas not being withdrawn from grazing for long enough. The lack of information has also led to farmers, who have lost grazing to fires, not being compensated fairly or even being over-compensated.

“When above-and below-ground plant production, together with efficient water usage, is taken into account, burnt grassland requires at least two full growing seasons to recover completely.”       

Prof Snyman says farmers frequently make the mistake of allowing animals to graze on burnt grassland as soon as it begins to sprout, causing considerable damage to the plants.

“Plant roots are more sensitive to fire than the above-ground plant material. This is the reason why seasonal above-ground production losses from fire in the first growing season after the fire can amount to half of the unburnt veld. The ecosystem must first recover completely in order to be productive and sustainable again for the long term. The faster burnt veld is grazed again, the longer the ecosystem takes to recover completely, lengthening the problem with fodder shortages further.  

Prof Snyman feels that fire as a management tool in semi-arid grassland is questionable if there is no specific purpose for it, as it can increase ecological and financial risk management in the short term.

Prof Snyman says more research is needed to quantify the impact of runaway fires on both grassland plant productivity and soil properties in terms of different seasonal climatic variations.

“The current information may already serve as valuable guidelines regarding claims arising from unforeseen fires, which often amount to thousands of rand, and are sometimes based on unscientific evidence.”

Prof Snyman’s research findings have been used successfully as guidelines for compensation aspects in several court cases.

 

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