A system for measuring the spatial distribution of the spectral emission of a measurement zone of an object, comprises: a first objective; means for selecting a portion of an image formed by the first objective; a diaphragm; light-dispersing means located in the vicinity of the diaphragm and allowing the light coming from the selecting means to be dispersed; and a second objective placed between the selecting means and the diaphragm, interacting with the first objective so that the aperture of the diaphragm is optically conjugated with the measurement zone by the first and second objectives. The first objective forms an image on a predetermined Fourier surface on which each point corresponds to an emission direction of the object for one particular wavelength. The selecting means have a selection surface shaped depending on the predetermined. Fourier surface, and the selecting means are placed on the predetermined Fourier surface.