Pierre Jules César Janssen

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Janssen, Pierre Jules César


Born Feb. 22, 1824, in Paris; died Dec. 23, 1907, in Meudon. French astronomer. Member of the Paris Academy of Sciences (1873) and of the Royal Society of London (1875). One of the founders of the spectral analysis of celestial bodies.

In 1868 and independently of J. N. Lockyer, Janssen invented the spectral method of observing solar prominences on the limb of the sun’s disk during periods when the sun was not in eclpse.


Neuimin, G. N. “P. Zh. Zhansen.” Izvestiia Russkogo astronomicheskogo obshchestva, 1909, issue 14, no. 8, pp. 285–90.
References in periodicals archive ?
In fact, the famous D3 line, first observed in a prominence during an eclipse, would lead to the discovery of helium on the Sun by Pierre Jules Cesar Janssen and Joseph Norman Lockyer [7, 8].