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28 January 2021 | Story Igno van Niekerk | Photo Supplied
Pictured from the left: Lucas Erasmus from the Department of Physics, Piet le Roux from the Astronomical Society of SA – Bloemfontein, Quinton Kaplan from the Department of Physics, Thinus van der Merwe from the Astronomical Society of SA – Bloemfontein. Front: Prof Matie Hoffman

In his book, The World is Flat, Thomas Friedman mentions how at first countries, then companies, and eventually communities went global. In true flat-world fashion, a combined team of the University of the Free State (UFS) and the Astronomical Society of South Africa – led by Prof Matie Hoffman, Associate Professor in the Department of Physics – participated in a once-in-a-lifetime event with their counterparts from the Ellinogermaniki Agogi School and the Skinakas Observatory in Greece.

On 21 December 2020, Earth was treated to the Jupiter-Saturn conjunction, when the two planets were only 0.1 degrees apart in the sky. Although conjunctions are regular phenomena, NASA mentions that the great conjunction of Jupiter and Saturn in 2020 was the closest since 1623 and the closest observable since 1226! A pinkie finger at arm’s length could cover both planets – although they were still millions of kilometres apart in space.

Planning started months ahead of the event, with the Ellinogermaniki Agogi Observatory in Greece and the Boyden Observatory in Bloemfontein chosen as the two selected vantage points. From both the Southern and Northern Hemisphere, the conjunction would be broadcast live on YouTube. As with any other technical project on an international scale, challenges arose. For example, in the Northern Hemisphere, it was already dark at 17:45 while the South African astronomers were still basking in sunlight until after 19:00. The conjunction would only be visible from South Africa after 19:30, almost two hours after it would be visible in Athens. The time was well used, with the event including a word of welcome by the Consul General of Greece in South Africa, Ioannis Chatzantonakis, presentations on Saturn and Jupiter, as well as a virtual tour of the Boyden Observatory, emphasising its connection with Greece through its first Director, Stefanos Paraskevopoulos. 

On Saturday, 19 December, the teams ‘gathered’ on opposite sides of planet Earth to do a dry run. One could sense the urgency and tension as both teams realised that they would have a huge captive audience on YouTube, and plans had to be made in case of connectivity challenges and if the weather did not allow the conjunction. As preparations progressed, Prof Hoffman was talking to his Greek counterparts and was simultaneously walking around with his laptop to share the landscape and activities via his webcam with colleagues in Greece. 

Monday 21 December 2020 – the weather prediction was correct. Clouds covered the Free State sky and scattered raindrops started to fall. Revert to Plan B. A recording made on Saturday evening was shared via the YouTube link, while a live feed of the conjunction from elsewhere in South Africa was arranged. From both sides of the world, information was shared about the history of the venues, as well as the marvel of what was happening in space. Fortunately, expert planetary photographer Clyde Foster was able to share a live feed just after 19:30 from the observatory at his home in Centurion, Gauteng. Those attending the event where visuals and speakers were together on one screen – yet thousands of kilometres apart – watching an event in outer space, will indeed agree with Thomas Friedman: the world is flat. The live-stream event of the conjunction was a catalyst that will result in continued collaboration between the UFS and colleagues in Greece in the field of astronomy. 

By the time of this writing, the livestream has reached more than 50 000 people.


News Archive

Research helps farmers save with irrigation
2017-02-15

Description: Irrigation research Tags: Irrigation research

Marcill Venter, lecturer in the Department of
Agricultural Economics at the University of the
Free State, has developed the mathematical
programming system, Soil Water Irrigation
Planning and Energy Management in order to
determine irrigation pump hours.
Photo: Rulanzen Martin

Her advice to farmers is that they should make sure they are aware of the total cost (investment and operating costs) of an irrigation system. In most cases the investment cost is low, but the operating cost over the lifetime of the system is high.

“It is very important to have a look at the total cost and to install the most economic system,” says Marcill Venter, lecturer at the University of the Free State (UFS), who has done research on the economic sustainability of water-pipe systems.

Irrigation systems important components for farming
This research comes at a time when many farmers are relying on their irrigation systems due to persistent drought and low rainfall during 2016. South Africa has also experienced an abnormal increase in electricity tariffs in recent years. Due to tariff increases which threaten the future profitability of irrigation producers, the Water Research Commission (WRC) has launched and financed a project on the sustainable management of irrigation farming systems. “I had the opportunity to work on the project as a researcher,” says Venter.

The heart of every irrigation system is the water pipes that bring life to crops and livestock, and this is what Venter’s research is about. “Water pipes are part of the whole design of irrigation systems. The design of the system impact certain factors which determine the investment and operating costs,” she says.

Mathematical system to help farmers
Venter and Professor Bennie Grové, also from the Department of Agricultural Economics at the UFS, designed the Soil Water Irrigation Planning and Energy Management (SWIP-E) programming model as part of the WRC’s project, as well as for her master’s degree. “The model determines irrigation pump hours through a daily groundwater budget, while also taking into account the time-of-use electricity tariff structure and change in kilowatt requirements arising from the main-line design,” says Venter. The model is a non-linear programming model programmed in General Algebraic Modeling System (GAMS).

Design of irrigation system important for sustainability

The main outcome of the study is that the time-of-use electricity tariff structure (Ruraflex) is always more profitable than the flat-rate structure (Landrate). The interaction between the management and design of a system is crucial, as it determines the investment and operating costs. Irrigation designers should take the investment and operating cost of a system into account during the design process. The standards set by the South African Irrigation Institute (SAII) should also be controlled and revised.

Water-pipe thickness plays major role in cost cuts
There is interaction between water-pipe thickness, investment and operating costs. When thinner water pipes are installed, it increases the friction in the system as well as the kilowatt usage. A high kilowatt increases the operating cost, but the use of thinner water pipes lowers the investment cost. Thicker water pipes therefore lower the friction and the kilowatt requirements, which leads to lower operating costs, but thicker pipes have a higher investment cost. “It is thus crucial to look at the total cost (operating and investment cost) when investing in a new system. Farmers should invest in the system with the lowest total cost,” says Venter.

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