Jacques Babinet (5.03.1794-21.X 1872) was a French physicist and astronomer and a member of the Paris Academy of Sciences (1840). He was born in Lusignan. After graduating from the École Polytechnique he was professor at Fontenay-le-Comte, from 1820 at the Collège Louis-le-Grand (Paris), and from 1841 he worked at the Bureau des Longitudes.
His research was in the field of optics, magnetism and molecular physics. He improved the air pump and built a hygrometer (1824), a goniometer and a polariscope. In optics he is known for Babinet's principle, which concerns diffraction by many apertures. He was the first to use a collimator lens (1839) and proposed an attachment for the tube of the polarising microscope (the Babinet compensator). He improved the spectrograph (the Babinet-Bunsen spectrograph). He studied double refraction, the Fraunhofer lines and the effect of the Earth's motion on the interference of light. He was the first to suggest (1829) that a particular wave of light could serve as a standard of length. A populariser of science.