Euclid Explanatory Supplement
Data Release Q1
Documentation release 1

Executive summary

The first Euclid Quick Data Release, Q1, comprises 63.1 deg² of the Euclid Deep Fields (EDFs) to nominal wide-survey depth. It encompasses visible and near-infrared space-based imaging and spectroscopic data, ground-based photometry in the $u$, $g$, $r$, $i$, and $z$ bands, as well as corresponding masks. Overall, Q1 contains about 30 million objects in three areas near the ecliptic poles arou nd the EDF-North and EDF-South, as well as the EDF-Fornax field in the constellation of the same name. Q1 also contains observations of a star-forming area in Lynd’s Dark Nebula 1641 in the Orion A Cloud, observed for technical purposes during Euclid’s performance-verification phase. This is a unique target, of a type not commonly found in Euclid’s nominal sky survey.