Euclid Telescope Discovers Previously Unknown Comet

The European Space Agency’s Euclid space telescope discovered the previously unknown comet C/2026 S1 (Euclid). It appeared in images taken from September 16 to 24, 2026. The Minor Planet Center confirmed it was a comet on October 8.

Mikko Pöntinen of the University of Helsinki spotted the object using a program that searches Euclid images for moving objects. A check of catalogs of known comets and asteroids found no matches. Pöntinen reported the observations to the Minor Planet Center, after which ground-based astronomers joined the follow-up observations.

Euclid was designed to produce deep images of distant galaxies, not to observe fast-moving objects in the Solar System. The telescope avoids the band of sky along the Solar System’s plane, where many asteroids and comets are found. In addition, its observing strategy usually involves observing each patch of sky only once.

According to ESA, the comet is about 1.3 billion kilometers from Earth. Its orbit passes above the plane of the Solar System, and it will take thousands of years to complete one orbit around the Sun. The comet is not suitable for ESA’s future Comet Interceptor mission. However, the process of detecting it and issuing an alert served as a test of how teams from the two missions might work together in the future.

Image: ESA/Euclid/Euclid Consortium/NASA, M. Pöntinen et al. 2026 CC BY-SA 3.0 igo · License

Translation editor: Ловушкин А.