Using Solar Orbiter’s Extreme Ultraviolet Imager (EUI), the team of scientists behind the mission was able to record part of the Sun’s atmosphere at extreme ultraviolet wavelengths. The last-minute modification to the instrument involved adding a small, protruding “thumb” to block the bright light coming from the Sun such that the fainter light of its atmosphere could be made visible.
“It was really a hack,” Frédéric Auchère, an astrophysicist at the Institute of Astrophysics of the Université Paris-Sud in France, and a member of the EUI team, said in a statement. “I had the idea to just do it and see if it would work. It is actually a very simple modification to the instrument.”
EUI produces high-resolution images of the structures in the Sun’s atmosphere. The team behind the instrument added a thumb to a safety door on EUI, which slides out of the way to let light into the camera so it can capture images of the Sun. If the door stops halfway, however, the thumb ends up shielding the bright light coming from the Sun’s disc in the center so that the fainter ultraviolet light coming from the corona (the outermost part of the atmosphere) can be visible.
The result is an ultraviolet image of the Sun’s corona. An ultraviolet image of the Sun’s disc has been superimposed in the middle, in the area left blank by the thumb hack, according to ESA.
The corona is usually hidden by the bright light of the Sun’s surface, and can mostly be seen during a total solar eclipse. The camera hack sort of mimics that same effect of the eclipse by blocking out the Sun’s light. The Sun’s corona has long baffled scientists as it is much hotter than the surface of the Sun with temperatures reaching 1.8 million degrees Fahrenheit (1 million degrees Celsius), one of the greatest mysteries surrounding our host star.
“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,” Daniel Müller, ESA’s Project Scientist for Solar Orbiter, said in a statement.