File:Big Dipper in Autumn (ann22042c-autumn).jpg
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editDescriptionBig Dipper in Autumn (ann22042c-autumn).jpg |
English: Image title: Big Dipper in Autumn Author: Giorgia Hofer Country: ItalyUrsa Minor, the Little Bear, is a constellation of the northern hemisphere, and it contains the northern celestial pole, in our current epoch marked by a bright star called Polaris or the Pole Star. For centuries Polaris has been used for navigation in the northern hemisphere, as it has been almost at the exact pole position for roughly 200 years. In the Middle Ages and antiquity, there was no pole star; the celestial north pole lay in a dark region and the Greeks considered the “Little She-Bear” as a companion of the “Great She-Bear”, which is more easily recognizable. The brightest stars of these constellations were alternatively also considered as chariots by the Greeks, as written in Aratus’s famous didactic poem from the 3rd century before the common era. The most famous asterism in Ursa Major, composed of seven stars, has different names across the (northern) world. While considered as a chariot by the Greeks, it is “The Northern Dipper” in China, and “The Seven Oxen” for the ancient Romans.It was also the navigational purpose that led to the name The Great She-Bear, Ursa Major; for the Greeks, travelling towards the direction of the horizon above which Ursa Major appears meant moving towards the land of the bears (northern Europe). An animal is clearly recognizable when taking into account all the fainter stars in the vicinity of the seven bright ones. They considered it a female bear because Greek mythology connects this animal with the nymph Callisto, whose story describes the initiation rituals for women.During the year the relative positions of Ursa Minor and the Big Dipper don’t change, but all stars appear to be moved in a circle around Polaris. This star pointing due north lies at the point where Earth’s rotational axis intersects the celestial sphere. The shift of constellations throughout the year is a globe-clock or a globe-calendar, used by ancient civilizations to measure the year, and to predict the changes of seasons. It helps to establish, for instance, the best time for sowing and sailing as winds change with the seasons. |
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Date | 15 December 2022 (upload date) | ||
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Author | Giorgia Hofer/IAU OAE | ||
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current | 22:58, 27 June 2023 | 5,858 × 3,835 (6.33 MB) | OptimusPrimeBot (talk | contribs) | #Spacemedia - Upload of https://www.iau.org/static/archives/images/large/ann22042c-autumn.jpg via Commons:Spacemedia |
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ISO speed rating | 2,000 |
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Date and time of data generation | 02:23, 12 July 2020 |
Credit/Provider | Giorgia Hofer/IAU OAE |
Source | International Astronomical Union |
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Software used | Adobe Photoshop CC 2015 (Windows) |
File change date and time | 09:19, 1 December 2022 |
Serial number of camera | 6000671 |
Lens used | 12.0 mm f/2.8 |
Date and time of digitizing | 02:23, 12 July 2020 |
Date metadata was last modified | 10:19, 1 December 2022 |
Unique ID of original document | C84B7272B8D87737059E1241D101E7B6 |
Contact information |
98-bis Blvd Arago Paris, None, F-75014 FRANCE |
IIM version | 4 |