 |
Joseph-Nicolas DelisleFrench astronomer and cartographer.
Date of Birth: 04.04.1688
Country:  France |
Content:
Biography of Joseph-Nicolas Delisle
Joseph-Nicolas Delisle was a French astronomer and cartographer born in Paris. He completed his education at the Mazarin College and then worked as an assistant to G. D. Cassini at the Paris Observatory. In 1712, he established his own small observatory.
Contributions in Russia
In 1714, Delisle began studying astronomy at the Paris Academy of Sciences under J. F. Maraldi. He became a professor of mathematics at the College de France in 1718. In 1726, he was invited to Russia as the first academician of astronomy to the newly established St. Petersburg Academy of Sciences.
During his time at the St. Petersburg Academy of Sciences until 1747, Delisle made significant contributions to the organization of astronomical science. He designed and equipped the academic astronomical observatory in the Kunstkamera building. His plans included degree measurements, determining the distances to the Sun and Moon, developing a theory of their movements, studying refraction, and preparing Russian scientists for the field.
Delisle also initiated systematic meteorological observations and observations of the aurora borealis in Russia in 1726. In 1735, he proposed the idea of creating the first time service in Russia. He led astronomical work necessary for the mapping of Russian territory conducted by the Academy of Sciences.
Cartography and Other Contributions
At Delisle's suggestion, the Geographic Department was created at the Academy of Sciences in 1739 to oversee cartography, and he became its first director. In 1728, he developed the equal intermediate conical map projection, which was most suitable for the elongated shape of countries like Russia. He also outlined a plan to establish a network of astro-points for the accurate mapping of Russia.
Delisle conducted various astronomical observations, focusing on observational astronomy, astrometry, and celestial mechanics. He observed solar and lunar eclipses, occultations of stars and planets by the Moon, studied sunspots, and measured the diameters of the Sun, Moon, and planets. He organized and processed observations for determining the parallaxes of the Sun and Moon, conducted by other astronomers such as N. L. Lacaille in Cape of Good Hope, J. J. F. Lalande in Berlin, J. Bradley in Greenwich, and A. N. Grishov in St. Petersburg.
Additionally, Delisle conducted observations of the transit of Venus across the Sun's disk in 1761 and 1769, and he created a map of the visibility of this phenomenon based on his own method. He also collaborated with G. Heinsius in observing comets in 1742 and 1744 and developed theories on their movements. He analyzed publications on comet theory after Isaac Newton and Edmond Halley and devised a method for determining comet orbits.
Delisle also made contributions to optics, particularly in the study of light diffraction. He discovered several important regularities in this phenomenon, including diffraction from objects of different shapes. He also dedicated significant attention to studying and translating the best works of Eastern scholars, such as Ulugh Beg, into European languages.
Legacy
Delisle trained a brilliant group of students in Russia and France, including L. Godin, Lalande, and Ch. Messier. He was a member of the Paris Academy of Sciences (1716), a member of the Royal Society of London, a foreign member of the St. Petersburg Academy of Sciences (1747), the Berlin Academy of Sciences, and many other academies and scientific societies.
In honor of his achievements, a crater on the Moon and asteroid number 12742 have been named after Joseph-Nicolas Delisle.