Spectroscope focused on a Bunsen flame The sodium

Spectroscope focused on a Bunsen flame

The sodium flame test

The Sun

Atoms in the cooler gas mantle around the Sun absorb the background hotter radiation we see at specific wavelengths

Fraunhofer’s original drawn lines overlayed on the visible spectrum - NB with red to the left (modern convention is blue to the left)

G 400 F 500 E D 600 C B A 700 nm Fraunhofer mapped out the puzzling dark lines in the solar spectrum labelling them A B C D… from the red end

3 P 3/2 Sodium D Lines 3 P 1/2 589. 0 nm 589. 6 nm 2 S 1/2 0. 597 nm

Fraunhofer Absorption Lines in the Sun’s Spectrum Na D lines Orange street lamps contain sodium

3 P 3/2 Sodium D Lines 3 P 1/2 589. 0 nm 589. 6 nm 2 S 1/2 0. 597 nm

Fraunhofer – the Father of Astrophysics

Thomson Higher Education

Commemorated by the German Stamp

G 400 F E 500 D 600 C B 700 nm

Noting that the solar spectrum was crossed by "innumerable" dark lines, Fraunhofer mapped their relative positions with precision. He developed an alphabetic system for labeling selected reference lines, assigning A to a line near the red end of the spectrum, D to the pair of dark lines associated with the bright orange streak he had observed in flame spectra, H to a line near the end of the visible violet, and I to a line in the ultraviolet. Fraunhofer's lines puzzled practitioners and theorists alike for over four decades after the publication of his spectral maps.

Noting that the solar spectrum was crossed by "innumerable" dark lines, Fraunhofer mapped their relative positions with precision. He developed an alphabetic system for labeling selected reference lines, assigning A to a line near the red end of the spectrum, D to the pair of dark lines associated with the bright orange streak he had observed in flame spectra, H to a line near the end of the visible violet, and I to a line in the ultraviolet. Fraunhofer's lines puzzled practitioners and theorists alike for over four decades after the publication of his spectral maps.

Fraunhofer Absorption Lines in the Sun’s Spectrum Na D lines Orange street lamps contain sodium Harry Kroto 2004