Europe will experience a total solar eclipse on Wednesday, 12 August. The path of totality will cross the westernmost parts of Iceland, Greenland, and Spain. The Solar Wind Sherpas team, led by mathematician Miloslav Druckmüller from the Faculty of Mechanical Engineering at Brno University of Technology, will deploy to five observation sites. As a result of major cuts to science funding by the Trump administration, the Czech-American team has lost part of its funding as well as access to a specialised NASA aircraft. Nevertheless, the expedition will go ahead as planned, thanks to a grant from the Czech Ministry of Education and financial support from the Faculty.

A total solar eclipse occurs when the Moon completely covers the Sun’s disc, briefly making it possible to observe the solar corona, which is normally hidden by the Sun’s intense light. Bright stars and some planets also become visible in the sky.

“The fact that we can observe a total solar eclipse is an incredible coincidence. No other body in the Solar System can produce a total eclipse of the Sun – they appear either larger or smaller than the Sun. But viewed from Earth, the Moon appears to be exactly the same size as the Sun, and that is what makes this breathtaking phenomenon possible,” explains Druckmüller.

This will be the Brno mathematicians’ sixteenth eclipse expedition. For this year’s expedition, they have selected five observation sites in Spain and Iceland. Depending on the location, they will have approximately two minutes to capture their images. The sites were therefore chosen with both the course of the eclipse and the likelihood of favourable weather in mind.

Since 2006, the Brno mathematicians have been collaborating on solar corona research with the team of astrophysicist Shadia Habbal from the University of Hawaiʻi’s Institute for Astronomy.

“The final image that I create after the eclipse using specialised software will be produced by processing approximately 100 GB of image data. Even though we observe the eclipse through the Earth’s atmosphere and therefore have less favourable observing conditions than a space probe, our expertise combined with US funding has enabled research demonstrating that total solar eclipses can produce images that, even today, cannot be obtained from space by any other means,” says Druckmüller.

The data collected help astrophysicists gain a better understanding of the physical processes that determine the structure of the corona and the sources of the solar wind.

Expedition Hit by US Government Funding Cuts

During the most recent eclipse over the United States and Mexico in April 2024, the Czech-American team was able, for the first time, to use a specialised NASA high-altitude research aircraft. The scientists had originally planned to use it for this year’s eclipse and the following two eclipses as well. However, major cuts to science funding by the Trump administration have changed those plans.

“Unfortunately, we have lost the opportunity to use the NASA aircraft for our observations. The University of Hawaiʻi has also lost a substantial share of its research funding,” Druckmüller explains.

The Czech part of the team has managed to partially offset the funding shortfall thanks to a project for which it received CZK 9 million from the Czech Ministry of Education over three years. The project, Investigating Physical Processes Determining Coronal Structures and Sources of the Solar Wind Based on Observations of Heavy-Ion Emission During Total Solar Eclipses, was launched in March 2026 and will run until 2029. It is funded under the INTER-EXCELLENCE II programme, specifically the INTER-ACTION subprogramme supporting bilateral Czech-US projects.

“Thanks to this funding, we were able to purchase 16 equatorial mounts, as well as cameras, lenses, and laptops this year,” adds Pavel Štarha, the project’s principal investigator and coordinator of the expedition’s technical arrangements. The expedition has also received financial support from the Faculty of Mechanical Engineering at Brno University of Technology.

Across the five observation sites, the team will have a total of 15 cameras, 40 cooled cameras, 55 lenses, and 20 control laptops at its disposal.

“One technical innovation this year is motorised focusing for manual lenses, which will speed up equipment preparation, particularly when weather conditions change rapidly,” Štarha explains. Students from the university’s Fotoklub Technika were also involved in developing the new components.

“We Would Go Even at Our Own Expense,” Says Miloslav Druckmüller

“Even if we hadn’t received the project funding, we would still have gone on the expedition. We probably wouldn’t have gone to Iceland, where everything is extremely expensive at the moment because of the eclipse, but we would have travelled to Spain on a much smaller scale and paid for it ourselves,” says Druckmüller.

“We did exactly that for our expedition to Mongolia in 2008. The PhD student who went with me earned the money for the trip by playing poker online.”

BUT Students from Fotoklub Technika Are Also Heading to Spain

A total of 28 expedition members will travel to Iceland and Spain. In addition to Czech and American scientists, the team will include BUT students and alumni. Václav Široký, a student and head of the university’s Fotoklub Technika, will be taking part in the expedition for the second time.

“A total eclipse is visually stunning and an absolutely unique experience, so it wasn’t difficult to find enthusiasts among our members who wanted to join me. For me personally, part of the appeal is also just how challenging eclipse photography is,” says Široký, adding that managing five cameras at once is no easy task.

Watch Václav Široký’s time-lapse of the 2024 total solar eclipse.

The Fotoklub Technika students will be stationed with Professor Druckmüller on Mount Trigaza in Spain. Their main observation site will be located next to a former mountain hut at an altitude of 1,658 metres above sea level. If the weather is favourable, the researchers plan to carry their lighter equipment all the way to the summit, at an altitude of 2,035 metres.

“The hut may be abandoned, but it will provide us with basic shelter. We can sleep inside in sleeping bags, cook for ourselves on large gas stoves, and collect water from mountain springs. Electricity is available on site thanks to a transmitter located there,” Široký says, describing the expedition’s practical arrangements. The team also had to obtain all the necessary permits from the local authorities for their stay on the mountain.

INFOBOX: About Total Solar Eclipses A total solar eclipse will occur on 12 August 2026. From the Czech Republic, it will only be visible as a partial eclipse, with the Moon covering approximately 85% of the Sun’s disc. The phenomenon will be observable in the early evening, at around 7 p.m. The previous total solar eclipse occurred on 8 April 2024 and was visible primarily in the United States, Mexico, Canada, and the central Pacific Ocean. The next total solar eclipse will be visible on 2 August 2027 and will be unusually long – lasting up to 6.5 minutes in locations including Egypt. The path of totality will begin in Spain and continue across North Africa, including Morocco and Egypt, before reaching Saudi Arabia. The Czech Republic will have to wait until 7 October 2135 to experience a total solar eclipse.

The Solar Wind Sherpas are an international team of scientists who travel around the world to observe total solar eclipses and collect scientific data. The team – aptly named given the enormous amount of equipment they transport to each, usually remote, observation site – is led by Shadia Habbal of the Institute for Astronomy in Honolulu, Hawaiʻi. To date, the Solar Wind Sherpas have undertaken 15 eclipse expeditions, including trips to India (1995), Syria (1999), Libya (2006), China (2008), the Arctic (2015), Indonesia (2016), and Australia (2023).

The team is one of only a few in the world to have exploited the diagnostic potential of observing coronal emission lines at multiple wavelengths, leading to a number of discoveries and successful scientific publications.

The researchers also study the invisible “colours” of the solar corona. Using cameras equipped with special filters and a custom-built spectrometer, they observe the behaviour of elements that have lost most of their electrons and emit light at very specific wavelengths. The most prominent elements include hydrogen, helium, iron, nickel, oxygen, carbon, and calcium. Each of them holds clues to the mysteries of the hot corona, which extends outward from the Sun and gives rise to the solar wind. More information about the Solar Wind Sherpas is available on the University of Hawaiʻi website.

Collecting the data is only the beginning of another demanding stage: processing it. This task rests entirely on Professor Miloslav Druckmüller. The software he has been developing since 1999 uses mathematically precise methods to extract the maximum amount of information from the collected data. The details revealed by combining tens or even hundreds of images allow astrophysicists at the University of Hawaiʻi to gain new insights into the solar corona.

A solar eclipse is an astronomical phenomenon that occurs when the Moon passes between the Earth and the Sun, partially or completely blocking the Sun from view. This can only happen during a new moon. The Sun’s diameter is approximately 400 times that of the Moon, but the Sun is also about 400 times farther from the Earth. This remarkable ratio makes it possible for the Sun, Moon, and Earth to align every 12 to 18 months.

A shadow roughly one hundred kilometres wide sweeps across the Earth, bringing darkness even during the daytime and causing temperatures to fall by several degrees. The glowing solar corona becomes visible around the Moon as it covers the Sun, while stars and some planets appear in the sky.

The path of totality is the area of the Earth’s surface from which a total solar eclipse can be observed. Depending on the Moon’s apparent size and its distance from the Earth, the path ranges from approximately 112 to 270 kilometres in width.

Researchers choose observation sites where the chances of favourable weather are as high as possible. Even a single cloud at the crucial moment can ruin an entire expedition. For this reason, the team tries to operate from several observation sites whenever possible.

White light is what we can see with the naked eye in the darkened sky during a total solar eclipse. It consists of photons scattered by free electrons moving along the Sun’s magnetic field lines – the Sun itself essentially being a giant magnet.

Most of us will remember a simple experiment from school: place a sheet of paper over a magnet and sprinkle iron filings on top. The filings automatically arrange themselves into arcs connecting the magnet’s north and south poles, making its magnetic field visible. During a solar eclipse, electrons play a similar role to the iron filings: because of their negative charge, their motion is governed by the magnetic field lines of our star.

Images of the solar corona by Miloslav Druckmüller are available at http://www.zam.fme.vutbr.cz/~druck/.