SATLASInfrared · Space
Euclid
OperatingOperating since 1 July 2023.
DR1-Foundation (about 1,900 deg² from the first 13 months of the survey, with images, catalogues and spectra) was released on 12 November 2026; weak-lensing and galaxy-clustering products follow in mid-2027.
A 1.2 m Korsch telescope feeding VIS, a 36-CCDCCDCharge-coupled device: a silicon pixel array that stores photo-electrons and shifts them to a readout amplifier. The workhorse optical detector; in X-rays, each photon's charge also measures its energy. imager with 0.1″ pixels in one broad 550–900 nm band, and NISP, which images in Y, J and H and takes slitlessslitless spectroscopyPlacing a dispersing element (often a grism, a prism–grating combination) in the beam with no slit, so every source in the field gets a spectrum at once. Efficient for surveys; spectra of neighbours can overlap. near-infrared spectra. Weak gravitational lensingweak gravitational lensingCoherent distortion of distant galaxy shapes, at the percent level, by mass along the line of sight. Averaged over millions of galaxies it maps dark matter and the growth of structure; it needs exquisite PSF control. of over a billion galaxy shapes and slitless spectroscopic redshiftsredshiftz = λ_observed/λ_emitted − 1, the stretching of light by cosmic expansion (or by recession). For distant sources it stands in for distance and look-back time: z ≈ 1 is about 8 Gyr ago, z ≈ 10 about 13.3 Gyr. of emission-line galaxies measure the expansion history and growth of structure, to test dark energydark energyWhatever drives the accelerating expansion of the Universe, about 69% of its energy density today. Measured through expansion history (supernovae, BAO) and the growth of structure (weak lensing, clustering). and gravity.
- Operator
- ESA
- Orbit
- Sun–Earth L2
- Aperture
- 1.2 m mirror
- VIS
- 550 nm – 900 nm
- NISP
- 900 nm – 2 µm
- Launch
- 1 July 2023
Passband
Sky coverage
The Euclid Wide Survey covers about 14,000 deg²square degreeUnit of solid angle: one degree by one degree on the sky. The whole sky is about 41,253 deg²; the full Moon covers about 0.2 deg². away from the Galactic planeGalactic planeThe plane of the Milky Way's disc, a band around the sky at Galactic latitude b ≈ 0°. Dense in stars, gas and dust: rich for stellar work, crowded and heavily extincted for extragalactic surveys, which usually avoid it. and eclipticeclipticThe plane of Earth's orbit projected on the sky; the Sun, Moon and planets stay close to it. Solar-system bodies and zodiacal light concentrate there, and spacecraft that must keep the Sun at a fixed angle often observe in strips perpendicular to it, so the ecliptic poles get the deepest coverage. in step-and-stare fields of about 0.5 deg²; three Deep Fields (North, Fornax, South) go about two magnitudesmagnitudeA logarithmic flux scale, m = −2.5 log₁₀(F/F₀): five magnitudes is a factor of 100, and larger is fainter. The naked eye reaches about 6; single Rubin exposures reach about 24 in r. deeper.
Archives
Its processing levels are mapped against other missions on the data levels page.
Key papers
Mission · 2025
Euclid. I. Overview of the Euclid mission (opens in a new tab)Euclid Collaboration, Mellier et al., A&A 697, A1
The spacecraft, instruments, survey and ground segment.
Data · 2026
Euclid First Data Release 1 (DR1) - Data release overview (opens in a new tab)Euclid Collaboration, Aussel et al., arXiv:2611.16510
About a billion objects from 1,975 deg² of the Wide Survey and 77 deg² of Deep Fields, and the papers documenting each product.
Instrument · 2025
Euclid. II. The VIS instrument (opens in a new tab)Euclid Collaboration, Cropper et al., A&A 697, A2
Instrument · 2025
Euclid. III. The NISP instrument (opens in a new tab)Euclid Collaboration, Jahnke et al., A&A 697, A3
Pipeline · 2026
Euclid Data Release 1 (DR1): VIS processing and data products (opens in a new tab)Euclid Collaboration, McCracken et al., arXiv:2611.15890
42,092 calibrated VIS frames, with their astrometric and photometric accuracy and remaining systematics.
Pipeline · 2026
Euclid Data Release 1 (DR1). Near-infrared processing and data products (opens in a new tab)Euclid Collaboration, Polenta et al., arXiv:2611.16119
How NISP raw frames become the 71,659 calibrated near-infrared images in DR1.
Pipeline · 2026
Euclid Data Release 1 (DR1): Photometric-redshift pipeline overview and validation (opens in a new tab)Euclid Collaboration, Hartley et al., arXiv:2611.15987
The photo-z, corrected photometry and object classes that DR1-Foundation releases.
Data · 2025
Euclid: Early Release Observations – Programme overview and pipeline for compact- and diffuse-emission photometry (opens in a new tab)Cuillandre et al., A&A 697, A6
The first public Euclid images and how they were processed.
Mission · 2011
Euclid Definition Study Report (opens in a new tab)Laureijs et al., arXiv:1110.3193
The science requirements and survey design the mission was built to meet.
Sources
Verified 15 November 2026.
- Euclid DR1 timeline (opens in a new tab)
- Euclid DR1 (opens in a new tab)
- Euclid's instruments (ESA) (opens in a new tab)
- Euclid survey (opens in a new tab)
- Euclid telescope (ESA) (opens in a new tab)
- Euclid VIS (ESA) (opens in a new tab)
Other infrared facilities: VLT, Spitzer, WISE / NEOWISE, JWST, SPHEREx, Roman, NEO Surveyor, ELT