Fraunhofer lines. Diagram of the Sun's spectrum, showing a set of dark absorption lines known as Fraunhofer lines. These are named after the German physicist Joseph von Fraunhofer (1787-1826), who discovered them in 1814. The spectrum is shown ranging from blue (right) to red (left), with the wavelength in angstroms across bottom. The absorption lines indicate the presence of certain elements in the Sun's atmosphere. Marked across top are the alpha, beta, gamma and delta lines of the Balmer series of emission lines for hydrogen, with the German word for hydrogen (Wasserstoff) also given.