Bernard Lyot: The Man Who Tamed the Sun's Light

A Youth Passionate About Optics

Born on February 27, 1897, in Paris, Bernard Lyot (1897-1952) developed an early passion for optics and mechanics. After studying at ESE (class of 1917), he joined the Meudon Observatory where he developed his first innovations.

The Revolutionary Invention: The Coronagraph

In 1930, Lyot invented the coronagraph, a device capable of artificially occulting the solar disk to study its corona. This major invention allowed for the first time the observation of:

• Solar prominences outside of eclipses
• The fine structure of the corona
• Solar magnetic phenomena

Its principle is based on an ultra-precise optical combination to eliminate light scattering.

Contributions to the Study of Planets

Lyot also revolutionized planetary observation:

• First precise measurements of the polarization of light from planets (1929)
• Study of the surfaces of Mars and Venus
• Development of polarizing filters for astronomy

His work on the polarization of lunar light confirmed the powdery nature of the lunar soil, a theory later validated by the Apollo missions.

The Pic du Midi Observatory

From 1943, Lyot transformed the Pic du Midi Observatory into a world center for solar astronomy. He installed his coronagraph there and trained a generation of astronomers. The observation conditions at 2877 meters above sea level allowed for observations of unprecedented quality.

Legacy and International Recognition

Lyot's inventions paved the way for:

• Modern heliophysics
• Solar observation satellites (such as SOHO)
• High-resolution imaging techniques

• The Gold Medal of the Royal Astronomical Society (1939)
• The Jules Janssen Prize (1947)
• The Bruce Medal (1951)

A lunar crater and an asteroid ((2452) Lyot) now bear his name.