Are you an EPFL student looking for a semester project?
Work with us on data science and visualisation projects, and deploy your project as an app on top of Graph Search.
Concept
Pole star
Summary
A pole star or polar star is a star, preferably bright, nearly aligned with the axis of a rotating astronomical body.
Currently, Earth's pole stars are Polaris (Alpha Ursae Minoris), a bright magnitude 2 star aligned approximately with its northern axis that serves as a pre-eminent star in celestial navigation, and a much dimmer magnitude 5.5 star on its southern axis, Polaris Australis (Sigma Octantis).
From around 1700 BC until just after 300 AD, Kochab (Beta Ursae Minoris) and Pherkad (Gamma Ursae Minoris) were twin northern pole stars, though neither was as close to the pole as Polaris is now.
In classical antiquity, Beta Ursae Minoris (Kochab) was closer to the celestial north pole than Alpha Ursae Minoris.
While there was no naked-eye star close to the pole, the midpoint between Alpha and Beta Ursae Minoris was reasonably close to the pole, and it appears that the entire constellation of Ursa Minor, in antiquity known as Cynosura (Greek Κυνόσουρα "dog's tail") was used as indicating the northern direction for the purposes of navigation by the Phoenicians. The ancient name of Ursa Minor, anglicized as cynosure, has since itself become a term for "guiding principle" after the constellation's use in navigation.
Alpha Ursae Minoris (Polaris) was described as ἀειφανής (transliterated as aeiphanes) meaning "always above the horizon", "ever-shining" by Stobaeus in the 5th century, when it was still removed from the celestial pole by about 8°. It was known as scip-steorra ("ship-star") in 10th-century Anglo-Saxon England, reflecting its use in navigation. In the Vishnu Purana, it is personified under the name Dhruva ("immovable, fixed").
The name stella polaris was coined in the Renaissance, even though at that time it was well recognized that it was several degrees away from the celestial pole; Gemma Frisius in the year 1547 determined this distance as 3°8'.
An explicit identification of Mary as stella maris with the North Star (Polaris) becomes evident in the title Cynosura seu Mariana Stella Polaris (i.e.
Official source
About this result
This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.
Ontological neighbourhood
Related courses (29)
CH-353: Introduction to electronic structure methods
Repetition of the basic concepts of quantum mechanics and main numerical algorithms used for practical implementions. Basic principles of electronic structure methods:Hartree-Fock, many body perturbat
MATH-351: Advanced numerical analysis
The student will learn state-of-the-art algorithms for solving differential equations. The analysis and implementation of these algorithms will be discussed in some detail.
MATH-201: Analysis III
Calcul différentiel et intégral.
Eléments d'analyse complexe.
Related concepts (30)
Circumpolar star
A circumpolar star is a star that, as viewed from a given latitude on Earth, never sets below the horizon due to its apparent proximity to one of the celestial poles. Circumpolar stars are therefore visible from said location toward the nearest pole for the entire night on every night of the year (and would be continuously visible throughout the day too, were they not overwhelmed by the Sun's glare). Others are called seasonal stars. All circumpolar stars lie within a circumpolar circle whose size is determined by the observer's latitude.
Chinese astronomy
Astronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twenty-eight mansions have been found on oracle bones unearthed at Anyang, dating back to the mid-Shang dynasty. The core of the "mansion" (宿 xiù) system also took shape around this period, by the time of King Wu Ding (1250–1192 BCE).
Draco (constellation)
Draco is a constellation in the far northern sky. Its name is Latin for dragon. It was one of the 48 constellations listed by the 2nd century astronomer Ptolemy, and remains one of the 88 modern constellations today. The north pole of the ecliptic is in Draco. Draco is circumpolar from northern latitudes, meaning that it never sets and can be seen at any time of year. List of stars in Draco Thuban (α Draconis) was the northern pole star from 3942 BC, when it moved farther north than Theta Boötis, until 1793 BC.