1861 - F.G.W. Sporer discovers
the variation of sun-spot 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''
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