A device for taking long-distance images includes, successively: an assembly, formed of spherical mirrors, having a first focal length, an optical relay assembly designed to render afocal the optical combination of this optical relay assembly and the assembly of spherical mirrors, a lens unit and an image sensor placed in the focal plane of the lens unit; the optical relay assembly being designed, for at least one focal length of the lens unit, to form the image from the exit aperture of the assembly constituted of mirrors on the entrance aperture of the lens unit. Preferably, the optical relay assembly is designed to form an image from the exit aperture of the spherical mirrors assembly in the entrance aperture of the lens unit.