A scanning multispectral telescope comprises an optical architecture arranged so as to focus the image of an object in the vicinity of a photodetection assembly, the area of focus being an image plane. The photodetection assembly comprises a number of parallel rows of photodetectors, each row being dedicated to a particular spectral band, each spectral band being centered on a mean wavelength. The telescope comprises means for acquiring and analyzing the images obtained from the rows of photodetectors using a phase diversity algorithm. Finally, the telescope comprises optical or mechanical means arranged in such a way that at least one of the rows of photodetectors is offset by a fraction of the mean wavelength which corresponds to it on an axis perpendicular to the image plane.