* Astronomy

Jacques Babinet (5 March 1794 in Lusignan (Vienne), France - 21 October 1872 in Paris, France) was a French physicist, mathematician, and astronomer who is best known for his contributions to optics.
Among Babinet's accomplishments are the 1827 standardization of the Angström unit for measuring light using the red Cadmium line's wavelength, and the principle (Babinet's principle) that similar diffraction patterns are produced by two complementary screens. He was the first to suggest using wavelengths of light to standardise measurements. His idea was first used between 1960 and 1983, when a meter was defined as a wavelength of light from krypton gas.
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