The Most Famous

ASTRONOMERS from France

This page contains a list of the greatest French Astronomers. The pantheon dataset contains 644 Astronomers, 49 of which were born in France. This makes France the birth place of the 4th most number of Astronomers behind Germany, and United Kingdom.

Top 10

The following people are considered by Pantheon to be the top 10 most legendary French Astronomers of all time. This list of famous French Astronomers is sorted by HPI (Historical Popularity Index), a metric that aggregates information on a biography’s online popularity. Visit the rankings page to view the entire list of French Astronomers.

1. Charles Messier (1730 - 1817)

With an HPI of 70.18, Charles Messier is the most famous French Astronomer. His biography has been translated into 74 different languages on wikipedia.

Charles Messier (French: [ʃaʁl me.sje]; 26 June 1730 – 12 April 1817) was a French astronomer. He published an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the Messier objects, referred to with the letter M and their number between 1 and 110. Messier's purpose for the catalogue was to help astronomical observers distinguish between permanent and transient visually diffuse objects in the sky.

2. Nicolas-Louis de Lacaille (1713 - 1762)

With an HPI of 65.20, Nicolas-Louis de Lacaille is the 2nd most famous French Astronomer. His biography has been translated into 59 different languages.

Abbé Nicolas-Louis de Lacaille (French: [nikɔla lwi də lakaj]; 15 March 1713 – 21 March 1762), formerly sometimes spelled de la Caille, was a French astronomer and geodesist who named 14 out of the 88 constellations. From 1750 to 1754, he studied the sky at the Cape of Good Hope in present-day South Africa. Lacaille observed over 10,000 stars using a refracting telescope.

3. Jérôme Lalande (1732 - 1807)

With an HPI of 65.11, Jérôme Lalande is the 3rd most famous French Astronomer. His biography has been translated into 43 different languages.

Joseph Jérôme Lefrançois de Lalande (French: [lalɑ̃d]; 11 July 1732 – 4 April 1807) was a French astronomer, freemason and writer.

4. Pierre Janssen (1824 - 1907)

With an HPI of 64.10, Pierre Janssen is the 4th most famous French Astronomer. His biography has been translated into 47 different languages.

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

5. Pierre Méchain (1744 - 1804)

With an HPI of 63.34, Pierre Méchain is the 5th most famous French Astronomer. His biography has been translated into 40 different languages.

Pierre François André Méchain (French pronunciation: [pjɛʁ fʁɑ̃swa ɑ̃dʁe meʃɛ̃]; 16 August 1744 – 20 September 1804) was a French astronomer and surveyor who, with Charles Messier, was a major contributor to the early study of deep-sky objects and comets.

6. Jacques Cassini (1677 - 1756)

With an HPI of 62.84, Jacques Cassini is the 6th most famous French Astronomer. His biography has been translated into 37 different languages.

Jacques Cassini (18 February 1677 – 16 April 1756) was a French astronomer, son of the famous Italian astronomer Giovanni Domenico Cassini. He was known as Cassini II. Cassini was born at the Paris Observatory. He was first admitted to Collège Mazarin after brief studies at his home observatory under his father. Later, he was admitted at the age of seventeen to membership of the French Academy of Sciences, he was elected in 1696 a fellow of the Royal Society of London, and became maître des comptes in 1706. While in England, he was acquainted with other famous astronomers such as Newton and Halley. Having succeeded to his father's position at the observatory in 1712, in 1713 he extended the Paris meridian, measuring the arc of the meridian from Dunkirk to Perpignan, and published the results in a volume entitled Traité de la grandeur et de la figure de la terre (1720). His two separate calculations for a degree of meridian arc were 57,097 toises de Paris (111.282 km) and 57,061 toises (111.211 km), giving results for Earth's radius of 3,271,420 toises (6,375.998 km) and 3,269,297 toises (6,371.860 km), respectively. This work represented Cassini's delve into the Earth figure debate. There were two main schools of thought, the Cartesians believed in a prolate spheroid, and the Newtonians in an oblate spheroid. Cassini sided with the Cartesians over the Newtonians, advocating for a prolate spheroid shaped earth. The Cartesians had support, but the Newtonians made separate observations seeming to disagree with the Cartesian idea. Cassini II likely realized that the Newtonian observations were more accurate, and stepped out of the scientific field. He only returned publicly after an attack from Anders Celsius. For his last few years he took up cartography, working with his son, Cassini de Thury or Cassini III, to create a new French map. This map was known as the Carte de Cassini, and was to be a very accurate map of France. Jacques Cassini's work on the ballistic pendulum has been a topic of controversy among historians of science. While some credit him with developing original work on the topic, others argue that he built upon the ideas of earlier scientists. It is difficult to determine the extent of Cassini's original contributions, as the available historical records are vague and incomplete. However, subsequent work on ballistic pendulums by Benjamin Robins (1707–1751), a British mathematician and engineer, suggests that he independently repeated many of the same results. Regardless of the extent of Cassini's original contributions, his work on the ballistic pendulum was significant in its time and helped to advance the field of ballistics. The device allowed for the measurement of the velocity of projectiles, which was important for the development of more accurate firearms and artillery.He also wrote Eléments d'astronomie on proper motion (1740), and published the first tables of the satellites of Saturn in 1716. He died at Thury, near Clermont, France.The asteroid 24102 Jacquescassini is named after him. Jacques Cassini married Suzanne Françoise Charpentier de Charmois. Their second son was astronomer César-François Cassini de Thury, who was also known as Cassini III.

7. Nicolas-Claude Fabri de Peiresc (1580 - 1637)

With an HPI of 60.32, Nicolas-Claude Fabri de Peiresc is the 7th most famous French Astronomer. His biography has been translated into 31 different languages.

Nicolas-Claude Fabri de Peiresc (1 December 1580 – 24 June 1637), often known simply as Peiresc, or by the Latin form of his name, Peirescius, was a French astronomer, antiquary and savant, who maintained a wide correspondence with scientists, and was a successful organizer of scientific inquiry. His research included a determination of the difference in longitude of various locations in Europe, around the Mediterranean, and in North Africa.

8. Jean Picard (1620 - 1682)

With an HPI of 59.99, Jean Picard is the 8th most famous French Astronomer. His biography has been translated into 29 different languages.

Jean Picard (21 July 1620 – 12 July 1682) was a French astronomer and priest born in La Flèche, where he studied at the Jesuit Collège Royal Henry-Le-Grand. He is principally notable for his accurate measure of the size of the Earth, based on a careful survey of one degree of latitude along the Paris Meridian.

9. Édouard Stephan (1837 - 1923)

With an HPI of 59.76, Édouard Stephan is the 9th most famous French Astronomer. His biography has been translated into 35 different languages.

Édouard Jean-Marie Stephan (31 August 1837 – 31 December 1923) was a French astronomer. His surname is sometimes spelled Stéphan in some literature, but this is apparently erroneous. He was born in Sainte Pezenne (today one of the districts of the town of Niort) and attended the Ecole Normale Superieure, and graduated at the top of his class in 1862.He was the director of the Marseille Observatory from 1864 to 1907 (until 1872 he was subordinate to Urbain le Verrier). In the early part of his career there, he had limited opportunities to do observations because he was preoccupied with improving the observatory. He discovered the asteroid 89 Julia in 1866. In 1867 he used the new telescope to observe a transit of Mercury.Between 1870 and 1875, Stephan systematically studied nebulae, precisely recording their positions and discovering many new ones. His goal was to enable the exact measurement of stellar proper motions by creating a reference system of fixed objects.In 1873, Stephan was the first person to attempt to measure the angular diameter of a star using interferometry, converting the 80 cm telescope at Marseille Observatory into an interferometer. He did this by obscuring the reflector with a mask containing two vertical slits. The star he chose to perform this experiment was Sirius. He did not succeed in resolving any stellar disks, but by 1874 had obtained an upper limit to stellar diameters of 0.158" (the true angular diameter of Sirius is 0.0059 arcseconds, and for comparison, the angular diameter of Alpha Centauri and Betelgeuse are 0.0145 and 0.05 arcseconds respectively).In 1881 he discovered NGC 5, and he discovered the galaxy NGC 6027 the following year using the 80 cm reflector.Among others, he discovered Stephan's Quintet, also known as "Arp 319", a group of five galaxies. Stephan made this discovery with the first telescope equipped with a reflection coated mirror.In 1884 the French Academy of Sciences awarded him the Valz Prize (Prix Valz). His name is associated with the periodic comet 38P/Stephan-Oterma, although Jérôme Coggia saw it first. He became a Chevalier of the Légion d'honneur in 1868 and an Officier of the Légion d'honneur in 1879.

10. Alphonse Borrelly (1842 - 1926)

With an HPI of 59.19, Alphonse Borrelly is the 10th most famous French Astronomer. His biography has been translated into 31 different languages.

Alphonse Louis Nicolas Borrelly (December 8, 1842 – February 28, 1926) was a French astronomer. He joined the Marseille Observatory in 1864. In the course of his career, he discovered a number of asteroids and comets, including the periodic comet 19P/Borrelly. The French Academy of Sciences awarded him the Prix Valz for 1903 and the Prix Lalande for 1909. The asteroid 1539 Borrelly was named in his honor. In 1913, he received the Prix Jules Janssen, the highest award of the Société astronomique de France, the French astronomical society.

People

Pantheon has 53 people classified as French astronomers born between 1497 and 1952. Of these 53, 2 (3.77%) of them are still alive today. The most famous living French astronomers include Catherine Cesarsky, and Françoise Combes. The most famous deceased French astronomers include Charles Messier, Nicolas-Louis de Lacaille, and Jérôme Lalande. As of April 2024, 3 new French astronomers have been added to Pantheon including Fernand Courty, Alexandre Schaumasse, and Louise du Pierry.