ESA’s Proba-2 satellite observed two partial solar eclipses, improving our understanding of the Sun’s atmosphere. ESA’s Proba-2 captured two partial solar eclipses on 8 April 2024. A solar eclipse occurs when the Moon comes between the Earth and the Sun, completely or partially covering the Sun from the Earth’s perspective. On April 8, lucky viewers in North America watched the moon completely block out the sun for several minutes, while viewers north and south of the “path of totality” saw a partial eclipse.

During the entire eclipse period, the Moon crossed Proba-2’s field of view twice, appearing as a partial solar eclipse. The satellite flies in an orbit about 700 km (435 miles) above the Earth’s surface, called a sun-synchronous orbit, with each orbit lasting about 100 minutes.

The video was created based on images taken by the Proba-2 SWAP telescope, which observes the Sun in extreme ultraviolet light. At these wavelengths, turbulence of the Sun’s surface and corona (the Sun’s expanded atmosphere) becomes visible. Since the Earth’s atmosphere does not allow light of such short wavelengths to pass, these measurements must be made from space.

A total solar eclipse provides a unique opportunity to view the Sun’s corona from the Earth’s surface using visible light. A faint corona is visible because the Moon blocks most of the Sun’s bright light. By comparing SWAP’s ultraviolet images with what telescopes on Earth see (in visible light), we can learn about the temperature and behavior of various structures in the corona.

Other solar missions have also made the most of the unique measurement opportunities provided by the eclipse. For example, ESA’s Solar Orbiter was located near the Sun during the entire eclipse, at a 90-degree angle to the Earth. This allowed it to support ground-based observations by monitoring the solar corona, including solar flares directed towards Earth.