Thanks to an artificial eclipse, the sun reveals its crown like never before
The solar crown seen by Aspiics, the prob-3 coronarographer. © ESA/SURBA-3/ASPIICS
It is a double world premiere that the European Space Agency (ESA) announced, this Monday, June 16, 2025. Thanks to an orbit flight maneuver at only 150 m from each other, the satellite duo of the probation-3 mission was able to capture the solar crown much closer to the limb (the edge of the sun, if you prefer) than ever.
The solar crown is the atmosphere of our star, never humanly visible because of the prodigious brightness of the latter, of the order of a million times. It was precisely the photographs taken during total solar eclipses that made it possible to discover this famous crown.
Cunning, the ESA launched in December 2024 two small satellites designed to make the flight in very close formation, so that one hidden the sun for the other. The technique is neither more nor less than that of close finger in front of his eye in order to hide someone’s face, for example. This technique is called coronography.
Nevertheless, the usually used coronographers being masks placed very close to the objective, they offer a fairly low precision and hide a large part of the solar crown. Obtaining a greater distance between the concealler and the imaging device allows greater precision, therefore accessing new knowledge.
The first artificial solar eclipse caused in orbit
Illustration of the orbit flight allowing solar concealment with probation-3. © ESA-P. Carril
The technology necessary for such a feat is quite incredible precision of 1.5 mm relative to the other. In addition, Sus probes have many advantages compared to natural eclipses, as explained on the ESA Andrei Zukhov website, principal researcher for Aspiics, hosted by the Royal Observatory of Belgium: “Our artificial eclipse images are comparable to those taken during a natural eclipse. The difference is that we can create our eclipse once every 19.6 h of orbit, while total solar eclipses occur naturally only once, very rarely twice a year. In addition to that, natural eclipses only last a few minutes, while probation artificial up to 6 hours. ”
On this assembly, we can see how much prob-3 makes it possible to imagine the solar crown more precisely than the other telescopes loaded with the same task:
The solar wreath observed by proba-3 and Soho, famous solar observatory. © ESA/NASA/SURBA-2/SURBA-3/SOHO/SWAP/ASPIICS/LASCO C2/WOW ALGORIT
What are the scientific objectives of proba-3?
The solar crown seen by Aspiics, the prob-3 coronarographer. © ESA/SURBA-3/ASPIICS
Among the many research subjects, the most obvious is this mystery of the great heat of the solar crown, less dense than the surface of the sun and yet much hot of a million degrees.
Joe Zender, a scientist member of the prob-3 project, specifies that “Seeing the first ASPIICS data is incredibly exciting. With the measurements made by another instrument on board, named Dara, Aspiics will help resolve persistent questions on our original star.”
According to ESA, the other objectives are the precise measure of solar irradiance, namely the amount of energy emitted in the form of radiation by the sun at all times, as well as the detection of solar electrons received in the terrestrial radiation belt.
“Although we are still in the commissioning phase, we have already managed to make a flight in training with unprecedented precision. This is what allowed us to capture the first images of the mission, which will undoubtedly be of great value for the scientific community”declares in turn Damien Galano, responsible for the mission.
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