Joseph von Fraunhofer

Born on 6 March 1787 to a family of glassmakers in Straubing, Bavaria, Joseph von Fraunhofer became not only a renowned glassmaker but also an accomplished physicist. Orphaned at the age of 11, Fraunhofer was apprenticed to glassmaker Philipp Anton Weichelsberger. In 1801 Fraunhofer survived the collapse of Weichelsberger’s house, an event that brought him to the attention of future king Maximilian I Joseph and his privy councilor Joseph von Utzschneider, who encouraged him to pursue an education and provided funding and textbooks in physics, optics, and mathematics. In 1806 Fraunhofer went to work for Utzschneider at his optical institute in the former Benediktbeuern monastery near Munich. By 1811 Fraunhofer was made a partner of the optical institute and head of the glassworks. During his tenure, he perfected the art of producing high-quality optical lenses, particularly for use in telescopes and other astronomical instruments. He developed the diffraction grating to separate light of different wavelengths and used his invention to discover dark absorption lines in the solar spectrum, which are now known as Fraunhofer lines. His work laid the foundation for the field of stellar spectroscopy. Fraunhofer was a member of the Royal Bavarian Academy of Sciences, was awarded an honorary doctorate from the University of Erlangen in 1822, and was knighted in 1824. He died at age 39 in 1826. (Photo credit: AIP Emilio Segrè Visual Archives, W. F. Meggers Collection)

Date in History: 6 March 1787