Fraunhofer Lines – The Legacy of a Genius

Orphaned at the age of 11, Joseph von Fraunhofer (1787-1826) in Germany joined a glass maker as an apprentice. His employer denied him even some oil for his night time study – fortunately, Fraunhofer caught the attention of a liberal man, Prince Elector Maximilian Josephs IV, who arranged for his studies and gave him some money.

Fraunhofer bought his freedom from apprenticeship with the funds he had and started learning Mathematics and optics at 19. He joined a monastery devoted to glass making. He had soon mastered the art of making fine glass . At the age of 31, he became the director of the optical institute. It was a time when good optics was in great demand by the military establishments in Europe as well as by surveyors. In fact, thanks to Fraunhofer, Bavaria took away a lot of glass making business from other manufacturers.

Joseph von Fraunhofer

Fraunhofer dispersed sunlight through a high quality prism and discovered dark absorption lines in the solar spectrum, since named after him as Fraunhofer Lines. That was in 1814. he showed the most prominent lines with letters that remain in use even today. He observed more than 570 lines and displayed 288 of them in an engraving. He invented diffraction grating for this purpose. In short, he transformed spectroscopy from a qualitative art into a quantitative science. He showed how to measure the wavelength of light accurately. He also studied the spectrum of star light and found that the Sirius and other first magnitude stars differed from each other and from the sun. He can truly be called the founder of stellar spectroscopy , through he was a master of dispersion of sunlight as well.

Fraunhofer died at the young age 39 years, because of natural poisoning from heavy-metal vapors used in glass making. True, he did not have knowledge of wavelengths and indicated them by painting them in different colors. But the dispersion of sunlight through a narrow slit advanced our knowledge of the sun and stars.

Biography of Joseph von Fraunhofer

International Year of Light

In mid December 2013, the UN General Assembly declared the year 2015 as the International Year of Light and Light-based Technologies (IYL 2015), this would not have been possible without the efforts of pioneers like Joseph von Fraunhofer who were the pioneers in the study of light.

By focusing on the topic of light science and it’s applications, the UN hopes to recognize the importance and role that light based technologies can plays in sustainable development and how it can provide solutions to some of the most pressing global challenges facing humanity in renewable energy, agricultural productivity and low cost health. To know more visit :

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