ESA’s Euclid space telescope begins its exploration of the dark Universe today. Over the next six years, Euclid will observe billions of galaxies across 10 billion years of cosmic history.
Euclid, one of the most precise and stable space telescopes ever built, was launched on July 1, 2023. During its first months in space, teams across Europe powered up, tested and prepared the mission for routine scientific observations. However, these “routine” scientific observations are not a piece of cake.
One of Euclid’s strengths is that it can observe a wide area of the cosmos at once. This is crucial for a mission whose main goal is to map more than a third of the cosmos in six years.
Euclid will follow a mode of observation called “step and look.” This means that the telescope will stare at one area of the cosmos for about 70 minutes, producing images and spectra, and then take four minutes to move to the next area. Throughout his mission, Euclid will make more than 40,000 of these “notes.”
“The number of galaxies that Euclid can observe in one observation is enormous, thanks to its attentive look at the cosmos, its long exposure time and its sensitivity,” explains Roberto Scaramella, scientist at the National Institute of Astrophysics (INAF) in Italy. and head of the consortium’s observation group since the beginning of the mission.
The most complete 3D vision so far
Roberto had to ensure that the survey was designed in a way that met the scientific objectives. One of Euclid’s main goals is to measure in more detail than ever the shapes of billions of galaxies over billions of years of cosmic history, to provide a three-dimensional view of the distribution of dark matter in our Universe. .
“To study the distortions of individual galaxies by dark matter, we need to observe at least 1.5 billion galaxies. Euclid will observe the shapes of about 50,000 galaxies with the necessary precision in a single shot, and he will detect many fainter ones,” adds Roberto.
Euclid has officially started its survey today. The telescope is scheduled to observe an area of 130 square degrees – more than 500 times the surface of the full Moon – over the next 14 days. This spot is located in the direction of the constellations of Caelum and Pictor, in the southern hemisphere.
The area of the cosmos that Euclid can observe with a single telescope orientation is larger than that of the full Moon.
Over the next year, Euclid will cover about 15% of its survey. This first year of cosmological data will be made available to the community in summer 2026. A smaller number of deep field observations are planned for publication in spring 2025.
About Euclid
Euclid is a European mission, built and operated by ESA, with contributions from NASA. The Euclid Consortium, made up of more than 2,000 scientists from 300 institutes in 13 European countries, the USA, Canada and Japan, was responsible for providing the scientific instruments and will be responsible for the analysis of the scientific data.