Medal commemorating Pierre Janssen and Joseph Norman Lockyer, French and English astronomers, 1868. In 1868, working independently of each other on spectroscopic studies of solar prominences, Pierre Jules Cesar Janssen (1824-1907) and Joseph Norman Lockyer (1836-1920) both observed a yellow line in the solar spectrum. Lockyer named it Helium from helios (sun). Reverse of a commemorative medal showing Phaeton driving his father Apollo's chariot near the sun. | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Heritage Images / Oxford Science Archive |
Taille de l’image : | 4237 px × 4122 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |