Fraunhofer maps solar spectral lines
Fraunhofer maps solar spectral lines
Overview
In 1814 the optician Joseph von Fraunhofer mapped hundreds of dark absorption lines in the solar spectrum while testing the finest prisms and gratings of his day. He showed the lines were fixed features of sunlight itself, cataloguing the strongest as letters still in use today. Decades later Kirchhoff and Bunsen identified the lines with chemical elements, opening spectroscopy as the tool that turned astronomy into astrophysics — the study of what stars are made of.