Winter Constellations

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Created for the OAE

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns. Taken from the Kottamia Astronomical Observatory, Cairo, Egypt, in December 2021, this image shows a few prominent winter constellations of the northern sky above the largest telescope in North Africa. The photograph depicts the constellation of Orion (prominently in the middle of the image) with its belt of stars pointing up to Aldebaran in Taurus and down to Sirius in Canis Major. Aldebaran is a reddish star that we see in front of the open star cluster of the Hyades (at the upper right edge of the image), which is the face of Taurus, the bull. The bright white star is Sirius, the brightest star in the night sky. Its Greek name (Seirios) means “the burner” and can be understood metaphorically as “the brightest”. This constellation has been represented in a variety of different cultures from all over the world. The ancient Egyptian religion also associates the constellation of Orion with a male figure, namely the god Osiris. It is told that Osiris was murdered by his envious brother Seth, who then dismembered the body and scattered the pieces all over the land. Fortunately, Osiris’s sister-wife Aset (Greek: Isis) is the most powerful sorceress and protective mother goddess. She collected the pieces, put them back together and breathed life back into the god. Aset is seen in the star pattern around the bright star Sirius at the bottom of the photograph. The Egyptian name for Sirius (and adjacent areas) is Sopdet (Greek: Sothis). The heliacal rise of Sirius in summer was a harbinger of the Egyptian new year.  Going north, we can spot a bluish star. This is Alhena, one of the stars in the feet of the zodiacal constellation Gemini, the twins, whose bright head stars would be beyond the upper left edge of the photograph. In the top centre we can see the star Elnath, in the constellation of Auriga, the charioteer. It is associated with Erichthonius, a hero of Greek mythology believed to be the inventor of the four-horse chariot. This same star is also considered the tip of the upper horn of Taurus, the bull. In Greek mythology Taurus is associated with the god Zeus who had sent him to rob a princess. It is commonly known that this Greek story was invented in order to include the Babylonian constellation in Greek mythology. In the Mesopotamian Gilgamesh saga, which is one of the oldest pieces of literature that we know (being traced back to the 3rd millennium), Taurus is the bull of heaven, sent by a jealous goddess and defeated by the king of Uruk to save his people. In the sky it harbours several interesting astronomical objects.
Credit: Mohamed Aboushelib/IAU OAE

Glossary Terms: Color , Constellation , Taurus , Orion
Categories: Naked Eye Astronomy , Stars

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Chilean Nights

video
Created for the OAE

Caption: Honourable mention in the 2022 IAU OAE Astrophotography Contest, category Time lapses of celestial patterns.   Shot in December 2020, this time-lapse shows the sky from San Pedro de Atacama, Chile, in the southern hemisphere. Right in the first frame we can see our home galaxy, the Milky Way, as well as both the Large and Small Magellanic clouds, two satellite galaxies orbiting the Milky Way. In the bottom of the image the bright stars Rigil Kentaurus and Hadar (also known as Alpha and Beta Centauri) are visible, both in the constellation Centaurus. Just above, we can also see the small constellation Crux, visible from the northern tropical circles southwards. It is important for navigation purposes because its longer axis indicates the direction of the celestial south pole. The bright whitish star in the top of the image and to the right of the Galaxy is Canopus, one of the brightest stars in the night sky, located in the constellation Carina. Canopus is the second brightest star in the sky, while Rigil Kentaurus is the third brightest. In some of the next frames, Orion, the great hunter, appears clearly with its bright stars and its characteristic asterism, the belt, composed of three aligned bright stars. Since this video was taken from the southern hemisphere, the Greek hero from the northern hemisphere seems to be performing a headstand. We can also see the planets Jupiter and Saturn in a close conjunction, even finding themselves in the significant beam of Zodiacal light setting down below the horizon. There are also a few meteors blinking in some of the frames, one of them with a long-lasting and developing trail. The very bright object rising from behind the volcanoes of the Andes, creating spectacular shadows and crepuscular rays, is the Moon. In the last frame we see the Moon next to Saturn and Jupiter.
Credit: Robert Barsa/IAU OAE

Glossary Terms: Astronomical Observatory , Constellation , Milky Way , Orion , Large Magellanic Cloud (LMC) , Small Magellanic Cloud (SMC) , Alpha Centauri
Categories: Galaxies , Milky Way and Interstellar Medium , Stars , Telescopes, Instruments and Observatories

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Chilean observatories at home office, by Robert Barsa, Slovakia

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Created for the OAE

Caption: Third place in the 2021 IAU OAE Astrophotography Contest, category Wide star fields. This rich panoramic image shows a range of constellations, deep sky objects and planets. The brightest point of light with a pale reddish hue (left of center) is the planet Mars. In the bottom far left of the image, located just above the sloped roof of the building are two points of light appearing very close to each other, these are the planets Jupiter (brighter) and Saturn. To the far right of the image the two fuzzy cloud-like objects are the Large and Small Magellanic Clouds. These are satellite dwarf galaxies of the Milky Way located at a distance of approximately 160,000 and 200,000 light years, respectively. The Andromeda Galaxy, which is located at an approximate distance of 2.5 million light years, appears in this image as a small, angled smudge between Mars and the brightest glow on the horizon (closer to the horizon). The bright glow is not from the Sun or the Moon, but the city lights of San Pedro de Atacama. Prominent constellations include: Orion – identified by the three stars forming Orion’s Belt; Taurus – a small triangle shaped collection of stars to the left of Orion and identified by the pale orange star (Aldebaran) at the vertex of the triangle; Canis Major – to the bottom right of Orion, identified by the bright star Sirius (the brightest star in the night sky) and three stars in the shape of a triangle just above the observatory dome in the foreground; Pegasus – identified by the trapezium shape diagonally below Mars. Other constellations include Andromeda, Perseus and Aries. Diverse cultures around the world have their own names and rich stories associated with these constellations and many others. To the top right of Orion’s Belt is an angled line of stars (Orion’s Sword) within which is a pinkish smudge (looks like a fuzzy star when observed with the unaided eye) that is the Orion Nebula – a stellar nursery located 1500 light years from Earth – where stars are formed. To the left of Taurus is a compact fuzzy smudge, and that is the Pleiades star cluster. The variation in the colour of stars is the result of temperature of the stars, for example, the red orange star to the bottom left of Orion’s Belt is the red giant star Betelgeuse. Cooler stars appear redder, compared to the higher temperature white and bluish stars. The colours in the image are enhanced because of the higher sensitivity of the digital camera compared to the human eye.
Credit: Robert Barsa/IAU OAE

Glossary Terms: Aries , Astronomy , Observatory
Categories: Naked Eye Astronomy , Telescopes, Instruments and Observatories

License: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons

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Stellar birth environment

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Caption: Snapshot of the formation of multiple protostars in the Orion Molecular Clouds with a closer look at each of them with the Atacama Large Millimeter/submillimeter Array and Very Large Array. Such an image provides unique insights of the process and early stages of star formation as well as the influence of the parent cloud in which they form.
Credit: ALMA (ESO/NAOJ/NRAO), J. Tobin; NRAO/AUI/NSF, S. Dagnello; Herschel/ESA
Credit Link

Glossary Terms: Protostar , Star Formation
Categories: Milky Way and Interstellar Medium , Stars

License: Creative Commons Attribution 3.0 Unported Creative Commons Attribution 3.0 Unported icons

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Winter Milky Way

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Created for the OAE

Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   Taken near Lake Misurina in the Veneto region of Italy in February 2019, this image shows a clear and starry sky over a winter landscape. We can see part of the Milky Way arc. From the left side, towards the south-east, we see Sirius, "The Burner" in Greek, the brightest star in the night sky. It is part of the constellation Canis Major, The Great Dog, one of the dogs of Orion, the great hunter, in Greek mythology. Orion’s other dog, Canis Minor, the Small Dog, is represented by the bright star Procyon and its fainter neighbours. The Greek star name means “The One [rising] before The Dog” and the star is seen at the top left side of the image just above the arc of the Galaxy. Orion lies to the right of Canis Major. We can spot its characteristic “belt”, an asterism composed of three bright stars aligned in a straight line.  Above the treetops to the right of Orion, the open star clusters of the Hyades and the Pleiades in the constellation Taurus, the Bull, are visible. According to ancient lore, these two clusters form a Celestial Gate directly next to the intersection of the great circles of the ecliptic and the Milky Way. In Greco-Roman mythology, Taurus is associated with the god Zeus who is said to have used a bull to seduce the Phoenician princess Europa. Above the constellation Taurus, we can see a bright star just above the arc of the Galaxy. This is Capella, the brightest star of the constellation Auriga, The Charioteer. This is one of the 88 modern constellations and is associated with the Greek hero Erichthonius of Athens. Hindu astronomy considers Capella as the heart of Brahma, one of the three major gods. The indigenous people of Bororo in Brazil have a constellation representing a cayman, comprising some of the stars of Auriga and some stars from neighbouring constellations. To the right of Taurus, we find the modern constellation Perseus with the bright double star cluster h+chi Perseii, which represents the metal of Perseus’s sabre in Greek mythology. Perseus is the hero who was sent out to prove himself, and happened to rescue Andromeda from the sea monster Cetus as the Roman poet Ovid wrote. We can also see the constellation Cassiopeia, associated with the queen and mother of Andromeda in Greek mythology. It is composed of five bright stars in the shape of a W, which was considered the asterism of The Key by the Greeks according to the poet Aratus. The recognisable shape is also associated with other mythologies: for instance, it represents the princess Sharmishtha in Hindu astronomy, a bat in Thailand, and a camel in native Arabic astronomy. In the gap between the trees, the Andromeda Galaxy is visible.
Credit: Giorgia Hofer/IAU OAE

Glossary Terms: Andromeda Galaxy , Milky Way , Taurus , Pleiades
Categories: Galaxies , Milky Way and Interstellar Medium , Naked Eye Astronomy

License: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons

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