Henri-Alexandre Deslandres facts for kids
Quick facts for kids
Henri-Alexandre Deslandres
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Henri-Alexandre Deslandres
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| Born | 24 July 1853 Paris, France
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| Died | 15 January 1948 (aged 94) Paris, France
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| Nationality | French |
| Alma mater | École Polytechnique |
| Known for | spectroheliograph |
| Awards | Janssen Medal (1896) Gold Medal of the Royal Astronomical Society (1913) Henry Draper Medal (1913) Fellow of the Royal Society |
| Scientific career | |
| Fields | astronomy |
| Institutions | Meudon Paris Observatories |
Henri Alexandre Deslandres (born July 24, 1853 – died January 15, 1948) was a famous French astronomer. He led the Meudon and Paris Observatories. Deslandres spent a lot of time studying the Sun's atmosphere and how it behaves.
Contents
Life and Work
Early Life and Military Career
Henri Deslandres studied at the École Polytechnique, a top French school. This was during a time of change in France. After graduating in 1874, he joined the military. He became a captain in the engineers.
However, he became more and more interested in physics. In 1881, he left the military. He joined Alfred Cornu's lab at the École Polytechnique. There, he started working on spectroscopy, which is the study of how light interacts with matter.
Scientific Discoveries
Deslandres continued his work on spectroscopy at the Sorbonne. He earned his doctorate degree in 1888. He created something called the deslandres table. This table helped find patterns in spectral lines. Spectral lines are like unique fingerprints that light from different elements leaves behind. His work was similar to what Johann Balmer did. It also helped lead to the development of quantum mechanics in the 20th century. Quantum mechanics is a branch of physics that studies very small particles.
In 1868, another astronomer, Pierre Janssen, made important observations of the Sun. He believed that physics and chemistry were becoming very important in astronomy. The French government gave Janssen money to build an observatory. This was the Meudon Observatory near Paris.
Leading Observatories
In 1889, Amédée Mouchez became the director of the Paris Observatory. He wanted to bring astrophysics into the main part of astronomy. Astrophysics uses physics to study stars and galaxies. So, he hired Deslandres. Deslandres helped develop the spectroheliograph. This is a special instrument that takes pictures of the Sun in specific colors of light. He developed it at the same time as George Hale in the United States.
In 1898, Deslandres joined Janssen at Meudon. He helped increase the number of scientists there. When Janssen passed away in 1907, Deslandres became the director. He started a program to expand the observatory. Deslandres was also the President of the Société Astronomique de France (SAF), which is the French astronomical society, from 1907 to 1909.
World War I and Later Years
When World War I started in 1914, Deslandres was already in his 60s. But he returned to active military service. He served as a major and later a lieutenant colonel in the engineers. After the war ended in 1918, he went back to Meudon. He stayed there until 1926. At that time, the Meudon Observatory joined with the Paris Observatory.
Deslandres continued his research until he passed away. Another astronomer, Raymond Michard, once said that Deslandres always seemed more like a soldier than a scholar.
Honours and Legacy
Awards and Recognition
Henri Deslandres received many important awards for his work:
- Gold Medal of the Royal Astronomical Society, (1913)
- Henry Draper Medal of the National Academy of Sciences, (1913)
- Prix Jules Janssen, the highest award from the French astronomical society, (1920)
- Bruce Medal of the Astronomical Society of the Pacific, (1921)
- He was also made a Fellow of the Royal Society.
Named After Him
Some things in space and science are named in his honor:
- The crater Deslandres on the Moon
- The Deslandres Prize from the French Academy of Sciences
- The Asteroid 11763 Deslandres
Images for kids
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Deslandres at the Fourth Conference International Union for Cooperation in Solar Research at Mount Wilson Observatory, 1910
