Fraun and Fiel spectral lines of the sun. Fraun-Hoe spectral lines in the solar spectrum and pointed atmospheric water vapor absorption lines. Fraunhofer spectral lines (translated as Fraunhofer lines in the mainland of China) are a series of spectral lines named after the German physicist Joseph von Fraunhofer (1787 - 1826). These are the Fraunhofer spectral lines originally regarded as the sun in the solar spectrum.