At the beginning of the 19th century, optics and glass processing underwent a huge technological leap. One of the most important pioneers was Joseph von Fraunhofer (1787-1826). Between 1807 and 1819, this famous optician worked at the newly established Institute of Optics and glassworks of the recently secularized monastery Benedikbeuern at the foot of the German Alps.
The glassworks in which Joseph von Fraunhofer’s workers manufactured lenses is now a small, very interesting museum (admission is free), where visitors are transported back in time to the early 19th century.
In a brick-tiled room, visitors are greeted by large furnaces containing agitators for glassmaking. Here, Fraunhofer succeeding in producing the lenses essential for improving the imaging quality of optical devices.
Joseph von Fraunhofer introduced a new era of optical devices to his colleagues Joseph von Utzschneider, Georg von Reichenbach and Georg Merz. Joseph Utzschneider, one of the first Bavarian industrialists, bought the optical institute and glassworks from the monastery, thus laying the foundation for Joseph von Fraunhofer’s glass manufacturing and research into light phenomena in Benediktbeuern.
Fraunhofer incorporated his lenses into optical devices such as telescopes, microscopes and opera glasses. In a small side room at the museum, visitors can admire some of these then-ultra-modern devices.
Due to the extreme heat of the ovens, the glassmakers had to wear protective clothing. They protected their faces with masks fitted with colored filters over the eye area. The workers held the masks in place with a bit clenched between their teeth.
Glass consists largely of quartz sand. Fraunhofer initially sourced his sand at Quarzbichl, a nearby quarry. Later, sand supplies came from Tirol. The sand was sieved to remove any impurities.
With his cutting edge optics, Fraunhofer discovered the eponymous Fraunhofer lines in the solar spectrum in 1814. Before it reaches the Earth, sunlight must first pass through various gases surrounding the Sun. Here, some wavelengths of the light spectrum are ‘swallowed’ by certain gases. This can be observed on Earth as very fine, black absorption lines in the optical spectrum of the sun: Fraunhofer lines. These teach us how the Sun’s environment, known as the photosphere, is constructed.