Pierre Janssen was born on February 22, 1824.
Pierre Janssen was born on February 22, 1824.
Pierre Janssen discovered the lines of helium in the spectra of the Sun on 18 August 1868 at Guntur (India).
In 1868 by Pierre Janssen.
Pierre Janssen discovered helium in 1868 during a solar eclipse while observing spectral lines in the sun's corona.
Norman Lockyer and Pierre Jules César Janssen
Edward H. Janssen was born in 1815.
Daniel Janssen was born in 1936.
Henk Janssen was born in 1890.
Peter Janssen was born in 1844.
Gerard Janssen was born in 1946.
Ray Janssen was born in 1937.
Johannes Janssen was born in 1829.