Joseph Fraunhofer

Joseph Ritter von Fraunhofer was a German physicist and optical lens manufacturer. He made optical glass and achromatic telescope objective lenses, invented the spectroscope, and developed diffraction grating. In 1814, he discovered and studied the dark absorption lines in the spectrum of the sun now known as Fraunhofer lines. The German research organization Fraunhofer Society, which is Europe's biggest Society for the advancement of applied research, is named after him.

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From 1812-1814, Joseph Fraunhofer studied the spectrum of solar light passing through a thin slit and recorded 500 dark lines. Newton missed seeing dark lines in 1666 because he shone light from the whole solar disk through a circular hole into his prisms