Pierre Janssen
FRENCH ASTRONOMER (1824-1907)
Pierre Jules Cesar Janssen; Pierre J. C. Janssen; Pierre J. Janssen; Jules Janssen; Pierre Jules César Janssen; Jules Janseen; Pierre-Jules Janssen; P.J.C. Janssen; Pierre Jules Janssen
Pierre Jules César Janssen (22 February 1824 – 23 December 1907), usually known as Jules Janssen, was a French astronomer who, along with English scientist Joseph Norman Lockyer, is credited with discovering the gaseous nature of the solar chromosphere, and with some justification the element helium.