Caption: Winner in the 2022 IAU OAE Astrophotography Contest, category Still images of celestial patterns.   This spectacular image shows a range of prominent constellations visible in the night sky over the desert of inner Mongolia, taken in August 2019. The yellowish star in the bottom left side is Arcturus, one of the brightest stars in the night sky, and the brightest in the constellation Boötes. The handle of the Big Dipper points towards this bright star and the Dipper is also visible above Boötes. The Northern Dipper (Bei Dou) is a traditional Chinese constellation. It is considered a chariot in which the Judges for Nobility are sitting. Arcturus is considered a single-star asterism, named the Horn, which forms part of the Chinese super-constellation for the spring, the Azure Dragon of the East. The front of the Northern Dipper points towards the star at the top of the photograph which is now called Polaris, the northern Pole Star. In ancient China, there was no bright star at the pole, so the stars in the nearest vicinity of the pole were considered to belong to the emperor and his family in the constellation the Purple Forbidden Palace. At least as early as mediaeval times, Polaris was considered part of the constellation of the Great Emperor of Heaven. Corona Borealis is also visible in the top right corner of this image, although not in its completeness. It is called the Coiled Thong in China. With its characteristic semi-circular shape, this is one of the smaller constellations of the 88 modern ones, but also can be traced back at least three or four millennia through the Roman “Crown”, the Greek wedding “Wreath”, and the Babylonian “Asterism of Dignity”. The modern name literally means “Northern Crown” in Latin. At the upper-right edge of the image, we find the part of the modern constellation Cassiopeia that is considered the Flying Corridor and an Auxiliary Road in ancient China. The W-shape of Cassiopeia is cut off by the edge of the photograph but the constellations to its south and southeast, Andromeda and Perseus, are clearly recognisable. Prominently we see the Andromeda galaxy, the most distant object that is visible to the unaided eye. It is located at the outermost outliers of the band of the Milky Way, which could explain why it has not been mentioned explicitly in ancient star catalogues, as it was mistakenly thought to be part of the Milky Way. The photograph also shows clearly reddish parts of the Milky Way that don’t appear bright to the naked eye, and also open clusters that are formed from the same molecular cloud, i.e., groups of stars with similar ages. This region is part of many big and small asterisms in traditional Chinese uranology.
Credit: Likai Lin/IAU OAE

Caption: Gagnant du concours d'astrophotographie 2022 de l'IAU OAE, catégorie Images fixes de motifs célestes. La Terre se déplaçant autour du Soleil, la position des étoiles dans le ciel nocturne semble changer au cours de l'année. Ce phénomène est bien illustré par cette mosaïque, dont les images ont été prises au cours des quatre saisons de l'année 2020 dans la région de la Vénétie, en Italie, et qui montre le mouvement apparent des constellations Ursa Minor et Ursa Major. Ursa Minor, la Petite Ourse, est une constellation de l'hémisphère nord. Elle contient le pôle céleste nord, marqué à notre époque par une étoile brillante appelée Polaris ou Étoile Polaire. Pendant des siècles, Polaris a été utilisée pour la navigation dans l'hémisphère nord, car elle se trouve presque à la position exacte du pôle depuis environ 200 ans. Au Moyen Âge et dans l'Antiquité, il n'y avait pas d'étoile polaire ; le pôle nord céleste se trouvait dans une région sombre et les Grecs considéraient la "Petite Ourse" comme une compagne de la "Grande Ourse", qui est plus facilement reconnaissable. Les étoiles les plus brillantes de ces constellations étaient également considérées comme des chars par les Grecs, comme l'indique le célèbre poème didactique d'Aratus datant du IIIe siècle avant l'ère commune. L'astérisme le plus célèbre de la Grande Ourse, composé de sept étoiles, porte différents noms dans le monde (nordique). Alors que les Grecs le considéraient comme un char, il est appelé "L'Ourse du Nord" en Chine et "Les Sept Bœufs" par les anciens Romains. Pour les Grecs, voyager dans la direction de l'horizon au-dessus duquel apparaît Ursa Major signifiait se diriger vers le pays des ours (l'Europe du Nord). Un animal est clairement reconnaissable si l'on tient compte de toutes les étoiles plus faibles qui se trouvent à proximité des sept étoiles brillantes. Ils ont considéré qu'il s'agissait d'une ourse femelle car la mythologie grecque associe cet animal à la nymphe Callisto, dont l'histoire décrit les rituels d'initiation des femmes. En haut à gauche, nous voyons une image prise un soir de printemps, tandis que l'image ci-dessous montre la même portion du ciel un soir d'été. Dans le sens inverse des aiguilles d'une montre, nous voyons le ciel en automne dans l'image en bas à droite, tandis que l'image en haut à droite montre finalement cette portion du ciel en hiver. Notez que les positions relatives d'Ursa Minor et de la Grande Ourse ne changent pas, mais que toutes les étoiles semblent être déplacées dans un cercle autour de Polaris. Cette étoile pointant plein nord se trouve au point d'intersection de l'axe de rotation de la Terre et de la sphère céleste. Le déplacement des constellations au cours de l'année constitue donc une horloge ou un calendrier planétaire, utilisé par les civilisations anciennes pour mesurer l'année et prédire les changements de saison. Il permet de déterminer, par exemple, le meilleur moment pour semer et naviguer, car les vents changent avec les saisons.
Credit: Giorgia Hofer/IAU OAE

Caption: This time-lapse documents the trajectory of the iconic Big Dipper across three frames taken in July 2020. Captured from three locations in Italy, Tre Cime di Lavaredo Auronzo di Cadore, Monte Rite, Cibiana di Cadore, and Casera Razzo, Vigo di Cadore, this visual odyssey showcases the captivating journey of the Big Dipper with the addition of trails of stars painting a celestial canvas. It not only traces the path of this renowned asterism but also features the rare appearance of comet Neowise C/2020 F3, an extraordinary event that graced our skies during July 2020.
Credit: Giorgia Hofer/IAU OAE (CC BY 4.0)

Caption: This time-lapse captures the movement of the stars alongside the majestic 64-metre Sardinia Radio Telescope (SRT) from the National Institute of Astrophysics (INAF), with special attention to the renowned Big Dipper against the backdrop of the celestial sphere. The camera pans as the famous asterism sinks in the sky while planes fly past and the radio telescope rotates. The harmonious interplay between the stellar pathways and the colossal dish of the radio telescope creates a mesmerising visual ode to the cosmic ballet taken in September 2019.
Credit: Antonio Finazzi/IAU OAE (CC BY 4.0)

Caption: The Big Dipper asterism gracefully moves above the otherworldly tufa formations of Mono Lake, California. The time-lapse captures the Big Dipper’s movement across the northern horizon until its inferior conjunction. At Mono Lake’s latitude (+38°), the stars of the Big Dipper remain circumpolar, except for Alkaid. The North Star sits 38° above the horizon, just outside the field of view in the top right. The lunar illumination bathes the landscape in a soft glow, gradually fading as the Moon sets, cloaking the scene in darkness.
Credit: Fabrizio Melandri/IAU OAE (CC BY 4.0)

Caption: A cosmic journey unfolds across continents in this time-lapse video which captures both iconic constellations from diverse corners of the world. Starting in China, the Big Dipper graces the night sky, a steadfast guide embedded in cultural narratives. Its luminance marks the beginning of this celestial odyssey. The two pointer stars on the end of the Big Dipper point to the North Star (Polaris) which appears to remain stationary as the sky rotates. From Nepal’s lofty peaks, the Big Dipper’s familiarity persists, a reliable fixture in the shifting panorama of the rotating planet. Moving to Chile, the Southern Cross adorns the firmament, emblematic of the southern skies. Frames from Chile showcase this constellation accompanied by the Milky Way Galaxy. In Namibia, a telescope from the H.E.S.S. Observatory appears in the video. Later, nestled beneath sheltering trees, the Big Dipper persists in its celestial prominence, appearing against a canvas of stars. Using varied techniques — fisheye lenses, static cameras, and Earth's movement-tracking — each frame unveils the Cross’s grandeur against diverse landscapes. These sequences — marked by star trails and Earth’s rotation—highlight the enduring presence of the Big Dipper and Southern Cross, bridging cultures and celestial beauty across hemispheres.
Credit: Jianfeng Dai/IAU OAE (CC BY 4.0)

Caption: Beneath the celestial ballet of star trails that weave their way across the night sky, the Beijing Forbidden City stands as a testament to ancient celestial connections in this image captured in March 2022. Designed with a cosmic alignment in mind, the palace echoes the orientation of the North Star, also known as Polaris, a celestial anchor that has long guided navigators and symbolised steadiness in the sky. It was believed that the Emperor embodied the earthly representation of this pole star, bridging the realms between heaven and earth. In this harmonious one-hour exposure captured with a smartphone, the streaks of stars trace their nightly journey across the firmament, converging toward the North Star, reflecting the precision of both architectural design and celestial paths.
Credit: Stephanie Ziyi Ye/IAU OAE (CC BY 4.0)