A life of research
Born in Bavaria, he trained in glassworking before becoming a leading specialist in optical instruments. His career united workshop skill, precise measurement and research.
He developed high-quality lenses and accurate comparison methods. His instruments enabled finer observations, including the stellar measurements later carried out by Bessel.
Understanding the contribution
Around 1814 he systematically studied dark lines crossing the Sun’s spectrum. He did not yet establish their atomic explanation, which emerged later with the development of spectral analysis.
The lines supplied reference positions for measuring colours and therefore wavelengths. Spectra would subsequently reveal the composition, temperature and motion of celestial bodies without requiring anyone to travel to them.