History of AstroSpectroscopy
These internet resources deal with the history of the evolution and development of astronomical spectroscopy. Knowing what came before is half the fun.

History of Astronomical Spectroscopy
From the Laser Stars home page - by John Talbot

1802 - 1860: Fraunhofer lines - Dark lines in the sun's spectrum discovered
1851 - 1895: Helium - Discovered in the Sun before on Earth
1896 - 1913: Proto-Hydrogen - Helium mistaken for Hydrogen in some stars
1840 - 1928: Nebulium - Spectroscopy of nebulae by Huggins
- 1930: Auroral lines - Spectral lines from Earth's aurora
1866 - 1929: P Cygni lines - novae with blue shifted lines
1867 - 1933: Wolf-Rayet spectra - Broad band emission lines
1869 - 1939: Coronium - Emission lines during solar eclipses in corona
1866 - 1942: Shell Stars - Stars having broad emission lines
1899 - 1946: The Balmer Jump - Hydrogen line jump in Vega-like stars

History Timeline

A History of Stellar Astronomy Timeline - by Neil Brandt - A quick history of stellar astronomy from 134 BC through the 1960s.