Euclid, color-composite image of the A2390 field. The blue channel is the I_E image, the green channel is Y_E, and the red channel is H_E. The whole field covers about 0.5 deg². The inset is centered on A2390 and covers 2′× 2′; which is approximately the field of view of the Wide Field Camera 3 NIR channel on board HST. In the whole Euclid, field, approximately 250 000 sources are identified in the CHI_MEAN detection image based on the Y_E, J_E, and H_E coadded mosaic.