Pierre Janssen

From Monoskop
Jump to navigation Jump to search

Pierre Jules César Janssen (22 February 1824 – 23 December 1907), also known as Jules Janssen, was a French astronomer inventor, and photographer who, along with the English scientist Joseph Norman Lockyer, is credited with discovering the gaseous nature of the solar chromosphere, and with some justification the element helium.

Astrophotography is a specialized type of photography that entails making photographs of astronomical objects in the night sky such as planets, stars, and deep sky objects such as star clusters and galaxies. Astrophotography was used to reveal objects that are too faint to observe with the naked eye, as both film and digital cameras can accumulate and sun pho- tons over long periods of time. Astrophotography posed challenges that were distinct from normal photography, because most subjects were usually quite faint and often small in angular size [1].