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Joseph Lepaute Dagelet
Joseph Lepaute Dagelet (1751–1788) was a French astronomer, clockmaker and mathematician who accompanied Lapérouse on his scientific circumnavigation, in the course of which he perished in the final shipwreck of the expedition. Dagelet's astronomical sightings gave precision to the maps posthumously published in the official ''Atlas du Voyage de la Perouse'' (Paris: L'Imprimerie de la Republique, An V, 1797). Young Dagelet arrived in Paris in 1767, welcomed by his uncles the renowned clockmakers Jean-André and Jean-Baptiste Lepaute, who held the brevet ''horlogers du Roi''. Through his aunt, Nicole-Reine Lepaute, wife of Jean-André, he discovered his aptitude for astronomy. From his arrival until 1772 he studied in the observatory of the Collège Mazarin, where he was guided by Joseph Jérôme Lefrançois de Lalande. In 1773 he departed for the South Seas with the expedition of Yves Joseph de Kerguelen de Trémarec; on his return he was made professor of mathematics at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, galaxies – in either observational astronomy, observational (by analyzing the data) or theoretical astronomy. Examples of topics or fields astronomers study include planetary science, Sun, solar astronomy, the Star formation, origin or stellar evolution, evolution of stars, or the galaxy formation and evolution, formation of galaxies. A related but distinct subject is physical cosmology, which studies the Universe as a whole. Types Astronomers usually fall under either of two main types: observational astronomy, observational and theoretical astronomy, theoretical. Observational astronomers make direct observations of Astronomical object, celestial objects and analyze the data. In contrast, theoretical astronomers create and investigate C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury (planet)
Mercury is the smallest planet in the Solar System and the closest to the Sun. Its orbit around the Sun takes 87.97 Earth days, the shortest of all the Sun's planets. It is named after the Roman god ' ( Mercury), god of commerce, messenger of the gods, and mediator between gods and mortals, corresponding to the Greek god Hermes (). Like Venus, Mercury orbits the Sun within Earth's orbit as an inferior planet, and its apparent distance from the Sun as viewed from Earth never exceeds 28°. This proximity to the Sun means the planet can only be seen near the western horizon after sunset or the eastern horizon before sunrise, usually in twilight. At this time, it may appear as a bright star-like object, but is more difficult to observe than Venus. From Earth, the planet telescopically displays the complete range of phases, similar to Venus and the Moon, which recurs over its synodic period of approximately 116 days. The synodic proximity of Mercury to Earth makes Mercury most ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mount Dagelet
Mount Dagelet is a glaciated mountain summit located in the Fairweather Range of the Saint Elias Mountains, in southeast Alaska, United States. The peak is situated in Glacier Bay National Park, south of Mount Crillon, and northwest of Mount La Perouse, which is the nearest highest peak. Topographic relief is significant as the mountain rises up from tidewater in less than nine miles. The mountain was named in 1874 by William Healey Dall of the U.S. Geological Survey, for Joseph Lepaute Dagelet (1751-1788), a French astronomer and mathematician who accompanied Lapérouse when he explored this coastal area in 1786. The first ascent of the peak was made July 29, 1933, by W. S. Child, C. S. Houston, and H. A. Carter. Climate Based on the Köppen climate classification, Mount Dagelet has a subarctic climate with cold, snowy winters, and cool summers. Weather systems coming off the Gulf of Alaska are forced upwards by the Fairweather Range (orographic lift), causing heavy prec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., it borders the Canadian province of British Columbia and the Yukon territory to the east; it also shares a maritime border with the Russian Federation's Chukotka Autonomous Okrug to the west, just across the Bering Strait. To the north are the Chukchi and Beaufort Seas of the Arctic Ocean, while the Pacific Ocean lies to the south and southwest. Alaska is by far the largest U.S. state by area, comprising more total area than the next three largest states (Texas, California, and Montana) combined. It represents the seventh-largest subnational division in the world. It is the third-least populous and the most sparsely populated state, but by far the continent's most populous territory located mostly north of the 60th parallel, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ulleungdo
Ulleungdo (also spelled Ulreungdo; Hangul: , ) is a South Korean island 120 km (75 mi) east of the Korean Peninsula in the Sea of Japan, formerly known as the Dagelet Island or Argonaut Island in Europe. Volcanic in origin, the rocky steep-sided island is the top of a large stratovolcano which rises from the seafloor, reaching a maximum elevation of at Seonginbong Peak. The island is in length and in width; it has an area of . It has a population of 10,426 inhabitants. The island makes up the main part of Ulleung County, North Gyeongsang Province, South Korea and is a popular tourist destination. The main city of Ulleung-do is the port of Dodong (), which serves as the main ferry port between Ulleung-do and the South Korean mainland. After tourism, the main economic activity is fishing, including its well-known harvest of squid, which can be seen drying in the sun in many places. History The island consists primarily of trachyandesite rock. A major explosive er ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brest, France
Brest (; ) is a port city in the Finistère department, Brittany. Located in a sheltered bay not far from the western tip of the peninsula, and the western extremity of metropolitan France, Brest is an important harbour and the second French military port after Toulon. The city is located on the western edge of continental France. With 142,722 inhabitants in a 2007 census, Brest forms Western Brittany's largest metropolitan area (with a population of 300,300 in total), ranking third behind only Nantes and Rennes in the whole of historic Brittany, and the 19th most populous city in France; moreover, Brest provides services to the one million inhabitants of Western Brittany. Although Brest is by far the largest city in Finistère, the ''préfecture'' (regional capital) of the department is the much smaller Quimper. During the Middle Ages, the history of Brest was the history of its castle. Then Richelieu made it a military harbour in 1631. Brest grew around its arsenal unti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Académie Des Sciences
The French Academy of Sciences (French: ''Académie des sciences'') is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research. It was at the forefront of scientific developments in Europe in the 17th and 18th centuries, and is one of the earliest Academies of Sciences. Currently headed by Patrick Flandrin (President of the Academy), it is one of the five Academies of the Institut de France. History The Academy of Sciences traces its origin to Colbert's plan to create a general academy. He chose a small group of scholars who met on 22 December 1666 in the King's library, near the present-day Bibliothèque Nationals, and thereafter held twice-weekly working meetings there in the two rooms assigned to the group. The first 30 years of the Academy's existence were relatively informal, since no statutes had as yet been laid down for the institution. In contrast to its British ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Champ De Mars
The Champ de Mars (; en, Field of Mars) is a large public greenspace in Paris, France, located in the seventh ''arrondissement'', between the Eiffel Tower to the northwest and the École Militaire to the southeast. The park is named after the Campus Martius ("Mars Field") in Rome, a tribute to the Roman god of war. The name alludes to the fact that the lawns here were formerly used as drilling and marching grounds by the French military. The nearest Métro stations are La Motte-Picquet–Grenelle, École Militaire, and Champ de Mars-Tour Eiffel, an RER suburban-commuter-railway station. A disused station, Champ de Mars, is also nearby. History Originally, the Champ de Mars was part of a large flat open area called Grenelle, which was reserved for market gardening. Citizens would claim small plots and exploit them by growing fruits, vegetables, and flowers for the local market. However, the plain of Grenelle was not an especially fertile place for farming. The constructio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jacques Alexandre César Charles
Jacques Alexandre César Charles (November 12, 1746 – April 7, 1823) was a French inventor, scientist, mathematician, and balloonist. Charles wrote almost nothing about mathematics, and most of what has been credited to him was due to mistaking him with another Jacques Charles, also a member of the Paris Academy of Sciences, entering on May 12, 1785. He was sometimes called Charles the Geometer. Charles and the Robert brothers launched the world's first unmanned hydrogen-filled gas balloon in August 1783; then in December 1783, Charles and his co-pilot Nicolas-Louis Robert ascended to a height of about 1,800 feet (550 m) in a manned gas balloon. Their pioneering use of hydrogen for lift led to this type of balloon being named a ''Charlière'' (as opposed to a Montgolfière which used hot air). Charles's law, describing how gases tend to expand when heated, was formulated by Joseph Louis Gay-Lussac in 1802, but he credited it to unpublished work by Jacques Charles. Charles ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Air Balloon
A hot air balloon is a lighter-than-air aircraft consisting of a bag, called an envelope, which contains heated air. Suspended beneath is a gondola or wicker basket (in some long-distance or high-altitude balloons, a capsule), which carries passengers and a source of heat, in most cases an open flame caused by burning liquid propane. The heated air inside the envelope makes it buoyant, since it has a lower density than the colder air outside the envelope. As with all aircraft, hot air balloons cannot fly beyond the atmosphere. The envelope does not have to be sealed at the bottom, since the air inside the envelope is at about the same pressure as the surrounding air. In modern sport balloons the envelope is generally made from nylon fabric, and the inlet of the balloon (closest to the burner flame) is made from a fire-resistant material such as Nomex. Modern balloons have been made in many shapes, such as rocket ships and the shapes of various commercial products, though the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nova
A nova (plural novae or novas) is a transient astronomical event that causes the sudden appearance of a bright, apparently "new" star (hence the name "nova", which is Latin for "new") that slowly fades over weeks or months. Causes of the dramatic appearance of a nova vary, depending on the circumstances of the two progenitor stars. All observed novae involve white dwarfs in close binary systems. The main sub-classes of novae are classical novae, recurrent novae (RNe), and dwarf novae. They are all considered to be cataclysmic variable stars. Classical nova eruptions are the most common type. They are likely created in a close binary star system consisting of a white dwarf and either a main sequence, subgiant, or red giant star. When the orbital period falls in the range of several days to one day, the white dwarf is close enough to its companion star to start drawing accreted matter onto the surface of the white dwarf, which creates a dense but shallow atmosphere. This atmosphe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WY Sagittae
WY Sagittae, also known as Nova Sagittae 1783, is a star in the constellation Sagitta which had a nova eruption visible in 1783. It was discovered on 26 July 1783 by the French astronomer Joseph Lepaute D'Agelet. It is usually difficult to precisely identify novae that were discovered hundreds of years ago, because the positions were often vaguely reported (for example the discoverer may have only reported the constellation where the nova occurred) and historically there was not a clear distinction drawn between different sorts of transient astronomical events such as novae and comet apparitions. However D'Agelet observed this nova with a mural quadrant, which produced coordinates accurate enough to allow modern astronomers to identify the star. D'Agelet reported the apparent magnitude of the star as 6, but Benjamin Apthorp Gould, who analysed D'Agelet's records, determined that what D'Agelet called magnitude 6 corresponds to magnitude 5.4 ± 0.4 on the modern magnit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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