Scientists have successfully modified a camera on the Solar Orbiter spacecraft to capture groundbreaking images of the Sun’s atmosphere, also known as the corona. This development is expected to shape future solar missions and instruments.
The Solar Orbiter’s Extreme Ultraviolet Imager (EUI) is designed to take high-resolution photos of the Sun’s atmosphere. However, a last-minute “hack” has expanded its capabilities, allowing it to see deeper into the corona than initially planned.
“It was really a hack. I had the idea to just do it and see if it would work. It is actually a very simple modification to the instrument,” says Frédéric Auchère, a member of the EUI team from the Institut d’Astrophysique Spatiale at Université Paris-Sud, in a statement.
The alteration involved adding a small protrusion, described as a “thumb,” to the safety door of the camera. As the door slides open to allow light in, halting it halfway allows the thumb to cover the Sun’s bright disc. This enables the camera to detect the significantly fainter ultraviolet light emanating from the surrounding corona. This operational approach has been termed the “occulter mode.”
Tests with the EUI occulter have been ongoing since 2021. The team is now confident about its effectiveness, publishing both a research paper and a video displaying the results. The video features an ultraviolet image of the Sun’s corona and includes a superimposed image from NASA’s STEREO mission, which viewed the Sun from a similar angle, helping to correlate features between the Sun and its atmosphere.
Traditionally, dedicated instruments called “coronagraphs” have been used to image the Sun’s corona. However, the new modification allows both the camera and the coronagraph to exist in the same instrument. “We’ve shown that this works so well that you can now consider a new type of instrument that can do both imaging of the Sun and the corona around it,” explains Daniel Müller, ESA’s Project Scientist for Solar Orbiter.
Scroll down to see video of the Solar Orbiter’s spectacular images
According to David Berghmans, the EUI Principal Investigator from the Royal Observatory of Belgium, this innovation allows scientists to explore previously obscured regions of the Sun’s atmosphere. “Physics is changing there, the magnetic structures are changing there, and we never really had a good look at it before. There must be some secrets in there that we can now find,” he says.
The Solar Orbiter is an international collaboration between the European Space Agency (ESA) and NASA, operated by ESA. This “hack” promises a lot of new scientific discoveries and will likely influence the design of future solar imaging instruments.