Dominique, comte de Cassini facts for kids
Quick facts for kids
Dominique, comte de Cassini
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Jean-Dominique, comte de Cassini, 1820. Lithograph by Julien-Léopold Boilly.
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| Born | 30 June 1748 Paris
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| Died | 18 October 1845 (aged 97) Thury
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| Citizenship | French |
| Known for | Terrestrial surveys |
| Children | Henri Cassini |
Jean-Dominique, comte de Cassini (born June 30, 1748 – died October 18, 1845) was a famous French astronomer. He came from a family of well-known scientists. His father, César-François Cassini de Thury, and his great-grandfather, Giovanni Domenico Cassini, were also important astronomers. Jean-Dominique continued their work, especially in mapping and understanding our planet.
Contents
Jean-Dominique Cassini: A Star Gazer's Life
Growing Up at the Observatory
Jean-Dominique was born right at the Paris Observatory, a famous place for studying stars and planets. In 1784, he took over from his father as the director of this important observatory. He had big plans to make the observatory even better. He wanted to fix it up and get new equipment.
However, in 1793, his plans faced problems. Because of political changes in France, his work became very difficult. He decided to leave his position on September 6. He was later held for seven months but was set free. After this, he moved away to Thury, where he lived until he passed away in 1845.
Exploring and Mapping the World
Jean-Dominique Cassini was not just an astronomer who looked at the sky. He also traveled and helped map the Earth.
Testing Watches at Sea
In 1770, he wrote about a trip he took to America in 1768. He went there to test special watches made by Pierre Le Roy. These watches were important for sailors to know their exact location at sea. Cassini helped make sure they worked well.
Connecting Observatories: The Anglo-French Survey
In 1783, his father suggested a big project. He wanted to connect the Paris Observatory with the Royal Greenwich Observatory in London. This would be done using a method called trigonometric survey. The goal was to figure out the exact location of the Greenwich Observatory.
This idea was accepted, and the Anglo-French Survey (1784–1790) began. Jean-Dominique Cassini visited England for this project. He worked with other famous scientists like Pierre Méchain and Adrien-Marie Legendre. They even met the famous astronomer William Herschel during their trip. The results of this important survey were published in 1791.
Completing the Map of France
Jean-Dominique also finished a huge project started by his father: creating a detailed map of France. This map was published in 1793 by the Academy of Sciences. It was so good that it became the base for the Atlas National in 1791. This atlas showed France divided into its different regions, called departments.
In recognition of his work, he was chosen as an honorary member of the American Academy of Arts and Sciences in 1788.
A Family of Scientists
Jean-Dominique Cassini wrote a book called Mémoires pour servir à l’histoire de l’observatoire de Paris in 1810. This book shared parts of a larger work he had planned. It also included stories about other scientists and a biography of his famous great-grandfather, Giovanni Domenico Cassini.
His youngest son, Henri Cassini, also became a notable scientist. Henri was a botanist, someone who studies plants. This shows how the Cassini family had a long history of contributing to science.
