Euclid RoI in an all-sky Mollweide projection. The blue borders enclose the 16 000 deg² RoI that contains the observed sky of the Euclid Wide Survey. The RoI excludes the Galactic and ecliptic planes. The triangular southern ‘island’ near RA = 330° is restricted in size since the LSST does not extend to more northern latitudes. The Euclid Deep Fields are shown in yellow and the auxiliary fields with red marks (not to scale).