Bernard Lyot

There’s much more to the Sun than the brilliant ball we see in the sky. Eruptions on the surface produce towers of hot gas, and a million-degree outer atmosphere extends far into space. Those structures are impossible to see in the glare of the solar disk, which is a million times brighter. But an astronomer born 125 years ago today invented a device to block out the disk, revealing the extended Sun.
Bernard Lyot was born in Paris. He trained as an engineer, then taught at a Paris high school. While there, he became interested in astronomy, and even built his own telescopes.
In 1920, he joined France’s Meudon Observatory. He worked there until his death, during an eclipse expedition, in 1952. He was especially interested in the Sun, and in developing new tools for studying it.
In the 1930s, he perfected the coronagraph. It uses a series of lenses and filters to block out the Sun. That reveals the eruptions, known as prominences, and the outer atmosphere — the corona. Before then, these