A new adaptive optics system reveals stunning, ultra-sharp views of the Sun’s corona—offering an unprecedented look at solar activity and hinting at answers to long-standing space weather questions.
In a major breakthrough, scientists from the U.S. National Science Foundation’s National Solar Observatory and the New Jersey Institute of Technology have captured the most detailed images ever of the Sun’s outer atmosphere, known as the corona. Using a powerful new technology called coronal adaptive optics, the team was able to remove the blurring effects of Earth’s atmosphere, revealing stunning, high-resolution images and movies of solar activity. Published in Nature Astronomy, their work opens exciting new possibilities for understanding the Sun’s extreme heat, solar eruptions, and the forces that drive space weather.
Unveiling the Sun’s Mysterious Corona
The Sun’s corona, its outermost atmospheric layer, has fascinated scientists for decades. Normally only visible during a total solar eclipse, the corona is known for its extreme heat, explosive eruptions, and massive loops of solar material. But until now, capturing clear images of this region has been nearly impossible. Earth’s atmosphere causes light to blur, making it difficult to study the corona’s fine details.
That’s starting to change. Scientists from the U.S. National Science Foundation’s National Solar Observatory and the New Jersey Institute of Technology have developed a breakthrough technology called coronal adaptive optics. This system removes the atmospheric blur and is already delivering the sharpest images and most detailed videos ever captured of the Sun’s outer atmosphere. Their results, published in Nature Astronomy, could transform our understanding of solar eruptions, space weather, and the mysterious heat of the corona.
Inside “Cona”: A High-Tech Leap
The new system, named “Cona,” is installed at the 1.6-meter Goode Solar Telescope in California. Built with support from the NSF and operated by NJIT’s Center for Solar-Terrestrial Research, this advanced technology compensates for the distortions caused by turbulence in Earth’s air, similar to the shaking during airplane turbulence.
“The turbulence in the air severely degrades images of objects in space, like our Sun, seen through our telescopes. But we can correct for that,” says Dirk Schmidt, NSO Adaptive Optics Scientist who led the development.
Solar Prominences and Plasma in Unprecedented Detail
Among the team’s remarkable observations is a movie of a quickly restructuring solar prominence unveiling fine, turbulent internal flows. Solar prominences are large, bright features, often appearing as arches or loops, extending outward from the Sun’s surface.
This time-lapse video of a prominence above the solar surface reveals its rapid, fine, and turbulent restructuring with unprecedented detail. The Sun’s fluffy-looking surface is covered by “spicules”, short-lived plasma jets, whose creation is still subject of scientific debate. The streaks on the right of this image are coronal rain falling down onto the Sun’s surface. This video was taken by the Goode Solar Telescope at Big Bear Solar Observatory using the new coronal adaptive optics system Cona. The video shows the hydrogen-alpha light emitted by the solar plasma. The video is artificially colorized, yet based on the color of hydrogen-alpha light, and darker color is brighter light. Credit: Schmidt et al./NJIT/NSO/AURA/NSF
A second movie replays the rapid formation and collapse of a finely structured plasma stream. “These are by far the most detailed observations of this kind, showing features not previously observed, and it’s not quite clear what they are,” says Vasyl Yurchyshyn, co-author of the study and NJIT-CSTR research professor. “It is super exciting to build an instrument that shows us the Sun like never before,” Schmidt adds.
This time-lapse movie shows the formation and collapse of a complexly shaped plasma stream traveling at almost 100 kilometers per second in front of a coronal loop system. This is likely the first time such a stream, which the scientists refer to as “plasmoid”, has been observed, leaving them wondering about the physical explanation of the observed dynamics. This video was taken by the Goode Solar Telescope at Big Bear Solar Observatory using the new coronal adaptive optics system Cona. The video shows the hydrogen-alpha light emitted by the solar plasma. The video is artificially colorized, yet based on the color of hydrogen-alpha light, and darker color is brighter light. Credit: Schmidt et al./NJIT/NSO/AURA/NSF
A third movie shows fine strands of coronal rain—a phenomenon where cooling plasma condenses and falls back toward the Sun’s surface. “Raindrops in the Sun’s corona can be narrower than 20 kilometers,” NSO Astronomer Thomas Schad concludes from the most detailed images of coronal rain to date, “These findings offer new invaluable observational insight that is vital to test computer models of coronal processes.”
Coronal rain forms when hotter plasma in the Sun’s corona cools down and becomes denser. Like raindrops on Earth, coronal rain is pulled down to the surface by gravity. Because the plasma is electrically charged, it follows the magnetic field lines, which make huge arches/loops, instead of falling in a straight line. This time-lapse video is composed of the highest resolution images ever made of coronal rain. The scientists show in the paper that the strands can be narrower than 20 kilometers. This video was taken by the Goode Solar Telescope at Big Bear Solar Observatory using the new coronal adaptive optics system Cona. The video shows the hydrogen-alpha light emitted by the solar plasma. The video is artificially colorized, yet based on the color of hydrogen-alpha light, and darker color is brighter light. Credit: Schmidt et al./NJIT/NSO/AURA/NSF
Another movie shows the dramatic motion of a solar prominence being shaped by the Sun’s magnetism.
This time-lapse movie of a solar prominence shows how plasma “dances” and twists with the Sun’s magnetic field. This video was taken by the Goode Solar Telescope at Big Bear Solar Observatory using the new coronal adaptive optics system Cona. The video shows the hydrogen-alpha light emitted by the solar plasma. The video is artificially colorized, yet based on the color of hydrogen-alpha light, and darker color is brighter light. Credit: Schmidt et al./NJIT/NSO/AURA/NSF
Solving the Coronal Heating Mystery
The corona is heated to millions of degrees–much hotter than the Sun’s surface–by mechanisms unknown to scientists. It is also home to dynamic phenomena of much cooler solar plasma that appears reddish-pink during eclipses. Scientists believe that resolving the structure and dynamics of the cooler plasma at small scales holds a key to answering the coronal heating mystery and improving our understanding of eruptions that eject plasma into space driving space weather—i.e., the conditions in Earth’s near-space environment primarily influenced by the Sun’s activity (e.g., solar flares, coronal mass ejections, and the solar wind) that can impact technology and systems on Earth and in space. The precision required demands large telescopes and adaptive optics systems like the one developed by this team.
The Tech Behind the Clarity
The GST system Cona uses a mirror that continuously reshapes itself 2,200 times per second to counteract the image degradation caused by turbulent air. “Adaptive optics is like a pumped-up autofocus and optical image stabilization in your smartphone camera, but correcting for the errors in the atmosphere rather than the user’s shaky hands,” says BBSO Optical Engineer and Chief Observer, Nicolas Gorceix.
Since the early 2000s, adaptive optics have been used in large solar telescopes to restore images of the Sun’s surface to their full potential, enabling telescopes to reach their theoretical diffraction limits—i.e., the theoretical maximum resolution of an optical system. These systems have since revolutionized observing the Sun’s surface, but until now, have not been useful for observations in the corona; and the resolution of features beyond the solar limb stagnated at an order of 1,000 kilometers or worse, levels achieved 80 years ago.
“The new coronal adaptive optics system closes this decades-old gap and delivers images of coronal features at 63 kilometers resolution—the theoretical limit of the 1.6-meter Goode Solar Telescope,” says Thomas Rimmele, NSO Chief Technologist who built the first operational adaptive optics for the Sun’s surface, and motivated the development.
Implications for the Future
Coronal adaptive optics is now available at the GST. “This technological advancement is a game-changer; there is a lot to discover when you boost your resolution by a factor of 10,” Schmidt says.
The team now knows how to overcome the resolution limit imposed by the Earth’s lowest region of the atmosphere—i.e., the troposphere—on observations beyond the solar limb and is working to apply the technology at the 4-meter NSF Daniel K. Inouye Solar Telescope, built and operated by the NSO in Maui, Hawaiʻi. The world’s largest solar telescope would see even smaller details in the Sun’s atmosphere.
“This transformative technology, which is likely to be adopted at observatories worldwide, is poised to reshape ground-based solar astronomy,” says Philip R. Goode, distinguished research professor of physics at NJIT-CSTR and former director at BBSO, who co-authored the study. “With coronal adaptive optics now in operation, this marks the beginning of a new era in solar physics, promising many more discoveries in the years and decades to come.”
Reference: “Observations of fine coronal structures with high-order solar adaptive optics” by Dirk Schmidt, Thomas A. Schad, Vasyl Yurchyshyn, Nicolas Gorceix, Thomas R. Rimmele and Philip R. Goode, 27 May 2025, Nature Astronomy.
DOI: 10.1038/s41550-025-02564-0
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