Swedish physicist and astronomer Anders Jonas Angstrom (1814–1874) was one of the founders of spectroscopy. His early work provided the foundation for spectrum analysis (analysis of the ranges of electromagnetic radiation emitted or absorbed). He investigated the sun spectra as well as that of the aurora borealis. In 1868, he established measurements for wavelengths of greater than 100 Frauenhofer. In 1907, the angstrom (A, equal to 1 × 10^–10 meters), a unit of wavelength measurement, was officially adopted.