An optical architecture for observation telescopes, in particular for telescopes intended to be installed on board a vehicle, such as a space satellite, for observing terrestrial areas, includes a concave and off-axis mirror which is aspherical or possibly spherical and reflects in the form of a convergent beam a beam consisting of radiation that it receives from a terrestrial area that it is observing, a dioptric and achromatic aperture correction plate inserted on the path of the convergent beam reflected by the mirror, a dioptric and achromatic field correction plate inserted on the path of the convergent beam reflected by the mirror on the downstream side of the aperture correction plate relative to the mirror, and a pupil on the path of the reflected convergent beam to obtain an off-axis field of view preventing central obscuration. It constitutes a simple way of imaging stereoscopically.