Fraunhofer also completed an
important theoretical work on diffraction and established the laws of
diffraction. One important
innovation that Fraunhofer made was to place a diffraction slit in front of the objective
of a measuring telescope in order to study the solar spectrum. He later made and used diffraction
gratings with up to 10,000 parallel lines per inch. By means of these gratings he was able
to measure
the minute wavelengths of the different colors of light. (Diffraction gratings will be discussed more later.)
Development of Diffraction Gratings