Example image of eyePlorer eyePlorer map for 'Fraunhofer lines': Joseph von Fraunhofer Optics Physics Spectral line Sun Visible spectrum William Hyde Wollaston Wavelength Sunlight Absorption (electromagnetic radiation) Chemical element Gustav Kirchhoff Robert Bunsen Earth's atmosphere Oxygen Balmer series Emission spectrum Cyan Yellow Dispersion (optics) Refractive index Helium star Timeline of microphysics List of refractive indices Abbe number Sun unit Bial's test Glass code Sodium layer Cosmic latte Frequency Addition Source of Optical Radiation Scientific phenomena named after people R Coronae Borealis variable Helium Redshift Hydrogen spectral series Spectralon Fraunhofer Bolometer Benediktbeuern Abbey Sodium Corrective lens On Vision and Colors Optical aberration