المستندات والموارد - نتائج البحث
نتائج البحث
Big Dipper in Four Seasons
صورة
أُنشئ لصالح OAE
الشرح: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.
As Earth moves around the Sun, the positions of the stars in the night sky appear to change over the course of the year. This is well exemplified in this mosaic, with images taken in all four seasons throughout 2020 in the region of Veneto, Italy, showing the apparent motion of the Ursa Minor and Ursa Major constellations.
Ursa 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.
In the top left, we see an image taken on a spring evening, while the image below shows the same portion of the sky on a summer evening. Going counterclockwise, we see the sky during autumn in the bottom right image, while the top right finally shows this portion of the sky in the winter. Note that 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 therefore 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.
المصدر: Giorgia Hofer/IAU OAE
مصطلحات المعجم:
المغرفة الكبرى , النجوم القطبية , دوران الأرض , القطب السماوي الشمالي , النجم القطبي , المجمة
فئات:
علم الفلك بالعين المجردة
الترخيص: المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات
هذا الملف على Zenodo ( صورة 2.39 MB)
Where the Sun Sets Every Month
صورة
أُنشئ لصالح OAE
الشرح: Third place winner in the 2023 IAU OAE Astrophotography Contest, category of Still images of sunrise and sunset location over the year.
Taken with a smartphone from San Rafael, Bulacan, Philippines, this series of images capture the changing position of sunset over the year owing to Earth’s axial tilt and orbit around the Sun. From January to December 2022, each image reflects the changing backdrop and position of the Sun at dusk. Observe the changing foliage and the appearance of an electricity pole in October. This collection serves as a visual testament to the celestial dance between Earth and the Sun, and the natural transformations on the ground.
المصدر: John Paul Pile/IAU OAE (CC BY 4.0)
مصطلحات المعجم:
الاعتدال , الانقلاب الشمسي , الانقلاب الصيفي , مسار الشمس (قوس النهار) , الانقلاب الشتوي
فئات:
علم الفلك بالعين المجردة
وسوم:
astrophotography
الترخيص: المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات
هذا الملف على Zenodo ( صورة 11.82 MB)
Fire of the Sky
صورة
أُنشئ لصالح OAE
الشرح: Winner in the 2023 IAU OAE Astrophotography Contest, category of Still images taken exclusively with smartphones/mobile devices.
In the serene landscapes of Lofoten, Norway on 28 March 2023, the sky was set ablaze by the aurora. The Northern (Southern) Lights, also known as aurorae, are natural light displays resulting from interactions between solar winds and Earth’s magnetic fields, as charged particles are redirected towards the north and south pole regions. In Norse legends, they are often depicted as a heavenly fire. In this scene, the celestial show is beautifully complemented by the silhouette of a lighthouse, as if the lighthouse ignited the mesmerising display overhead. Caught off-guard by this dazzling spectacle, the photographer swiftly captured the moment with a smartphone. This is a testament to the breathtaking surprises nature offers and the impressive capabilities of modern devices.
المصدر: Stephanie Ziyi Ye/IAU OAE (CC BY 4.0)
مصطلحات المعجم:
الشفق القطبي , العاصفة الجيومغناطيسية , الشفق القطبي الشمالي
فئات:
علم الفلك بالعين المجردة
وسوم:
astrophotography
الترخيص: المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات
هذا الملف على Zenodo ( صورة 1.67 MB)
Portrait of a Bat
صورة
أُنشئ لصالح OAE
الشرح: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.
Taken in November 2019 from the Doi Inthanon National Park, Chiang Mai, Thailand, this image captures the notable northern constellation Cassiopeia, in the shape of the letter M. Although the official constellation name is the Latinised version of the name of queen “Kasseipeia” from Greek mythology, these five bright stars were considered a constellation in many cultures around the world and they are associated with diverse stories. In Thailand, for example, the constellation represents a Bat, while in Hawaiian culture it is called 'Iwa Keli'i, the chief frigate bird.
For the Navajo in North America, the bright stars are the central part of the celestial mother (of all stars and humans) revolving around the celestial pole together with her husband, the celestial father (of all stars and humans) seen in the constellation of Ursa Major. For the Maya it was part of the huge constellation of the Hole-Backed Caiman, and for the Inuit a Lamp Stand and a Blubber Container.
In ancient China, the bottom-left star was associated with the mythological general Wangliang who drove four horses, represented by the two bright and two fainter stars of the M’s next stroke (from upper-left to lower-middle). The remaining two bright stars and a couple of the other fainter ones are considered a Flying Corridor, a sort of highway, next to the Emperor’s Forbidden Palace that is located at the northern polar region.
On the island of Tonga in the South Pacific, this asterism is considered the Wing of Tafahi and it is not clear if this refers to the shape of the island of Tafahi, or if it is based on an error and originally referred to a wing of the Polynesian hero Tafaki.
The various colours of the stars indicate their temperatures, with redder stars being relatively cooler on their surface than blue and white stars.
المصدر: Thanakrit Santikunaporn/IAU OAE
مصطلحات المعجم:
اللون , مجموعة نجمية او حشد نجمى , المجمة
فئات:
علم الفلك بالعين المجردة
الترخيص: المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) المشاع الإبداعي نَسب المُصنَّف 4.0 دولي (CC BY 4.0) أيقونات
هذا الملف على Zenodo ( صورة 9.65 MB)
The Prime Meridian
صورة
الشرح: The prime meridian is defined as zero degrees longitude and runs from the North Pole through Greenwich in London to the South Pole. It is represented as a bright red line on this schematic Earth map. The horizontal line corresponds to the equator, while the antimeridian itself forms the outer edges at 180 degrees to the west and east.
المصدر: Wikicommons user Kmf164
رابط المصدر
مصطلحات المعجم:
خط الاستواء , خط الطول الرئيسي
فئات:
كوكب الأرض
الترخيص: الملكية العامة الملكية العامة أيقونات
ملف
( صورة
563.81 kB)
