Chronology of Solar Astronomy

1613 Galileo Galilei uses sunspot observations to demonstrate the rotation of the Sun.
1619 Johannes Kepler postulates a solar wind to explain the direction of comet tails.
1802 William Wollaston observes dark lines in the solar spectrum.
1814 Joseph Fraunhofer systematically studies the dark lines in the solar spectrum.
1834 Hermann Helmholtz proposes gravitational contraction as the energy source for the Sun.
1843 Heinrich Schwabe announces his discovery of the sunspot cycle and estimates its period to be about ten years.
1852 Edward Sabine shows that sunspot number is correlated with geomagnetic field variations.
1859 Richard Carrington discovers solar flares.
1860 Gustav Kirchoff and Robert Bunsen discover that each element has its own distinct set of spectral lines and use this fact to explain the solar dark lines.
1861 F.G.W. Sporer discovers the variation of sunspot latitudes during a solar cycle.
1863 Richard Carrington discovers the differential nature of solar rotation.
1868 Pierre-Jules-Cesar Janssen and Norman Lockyer discover an unidentified yellow line in solar prominence spectra and suggest it comes from a new element which they name "helium''.
1893 Edward Maunder discovers the 1645-1715 Maunder sunspot minimum.
1904 Edward Maunder plots the first sunspot "butterfly diagram''.
1906 Karl Schwarzschild explains solar limb darkening.
1908 George Hale discovers the Zeeman splitting of spectral lines from sunspots.
1942 J.S. Hey detects solar radio waves.
1949 Herbert Friedman detects solar X-rays.
1960 Robert Leighton, Robert Noyes, and George Simon discover solar five-minute oscillations by observing the Doppler shifts of solar dark lines.
1961 H. Babcock proposes the magnetic coiling sunspot theory.
1970 Roger Ulrich, John Leibacher, and Robert Stein deduce from theoretical solar models that the interior of the Sun could act as a resonant acoustic cavity.
1975 Franz-Ludwig Deubner makes the first accurate measurements of the period and horizontal wavelength of the five-minute solar oscillations.