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: Gagnant du concours d'astrophotographie 2023 de l'UAI OAE, catégorie Images fixes avec smartphones-appareils mobiles : Traînée d'étoiles dans l'hémisphère sud avec pollution lumineuse à un niveau 4 sur l'échelle de Bortle, par Slamat Riyadi. Cette photo, à couper le souffle, prise sous le ciel nocturne clair du village de Linggamekar, Cilimus, Kuningan, Java occidental, Indonésie, le 25 juin 2020, montre des traînées d'étoiles balayant les cieux de l'hémisphère sud. Elle est l'une des six lauréates dans la catégorie des images fixes prises exclusivement avec des smartphones/appareils mobiles. Les traînées d'étoiles sont dues à la rotation de la Terre qui provoque le mouvement apparent des étoiles, créant ces arcs de lumière envoûtants lorsqu'ils sont suivis sur de longues périodes. Ici, le point autour duquel tournent les étoiles (le pôle céleste sud) est proche de l'horizon, car l'image a été prise près de l'équateur. Le photographe a utilisé la fonction de suivi des étoiles d'un smartphone, qui a capturé une série d'images sur une période prolongée et les a empilées. L'arbre remarquable au premier plan ajoute de la profondeur à l'image, contrastant avec le mouvement céleste et l'immobilité terrestre, tout en masquant une partie de la pollution lumineuse environnante. Les différentes régions du monde offrent des perspectives variées et étonnantes sur le ciel nocturne, soulignant l'importance de préserver le ciel noir partout dans le monde.
Credit: Slamat Riyadi/UAI OAE (CC BY 4.0)

Caption: This video shows the Milky Way’s sprawling brilliance across the celestial expanse. Among the stars’ grand theatre, the Southern Cross constellation claims its place in the scene, distinguished by its distinctive cross shape as seen in the top of this video and slightly to the right just over the Milky Way, slowly disappearing as the video progresses. This celestial marker, a prominent feature in the southern hemisphere, holds cultural and navigational significance, having served as a navigational guidepost for centuries. Accompanying the Milky Way’s grandeur are the two Magellanic clouds, celestial companions seen dancing in the distant sky. The Carina Nebula adds its ethereal glow to the cosmic panorama, painting a radiant hue against the darkness. In the midst of this celestial ballet, a gentle green hue envelops the atmosphere, a phenomenon known as airglow, adding a touch of subtle luminescence to the night sky. The terrestrial also makes an appearance, with planes flying overhead and vehicles driving between observatory buildings. This time-lapse, taken from the La Silla Observatory in Chile, is a window to the captivating dance of stars, offering a glimpse into the awe-inspiring beauty of our galaxy and the celestial landmarks that grace the southern sky.
Credit: José Rodrigues/IAU OAE (CC BY 4.0)

Caption: Taken from San Pedro de Atacama, Chile, in June 2023, this time-lapse reveals the celestial ballet that unfolds as the Southern Cross takes its majestic journey across the sky, pointing the way to the South Celestial Pole around which the sky rotates, until it gracefully sets. The star-studded canvas showcases the grandeur of the Milky Way, adorned by the rotating Large and Small Magellanic Clouds swirling around the Southern Celestial Pole. The prominent constellations of Crux, Centaurus, Scorpius, and the former Argo Navis (Carina, Puppis, Vela) are also visible. The spectacle begins just after nightfall, capturing the radiant descent of Canopus, a beacon about to dip below the horizon. Throughout the sequence, there is a subtle presence of passing aeroplanes, fleeting headlights of cars, drifting clouds, and the ethereal airglow. At a stunning moment, a vivid meteor streaked across the sky, a breathtaking fireball briefly igniting the right lower corner around the 41st second mark. As the sequence progresses, the rising moon elegantly illuminates the landscape, casting its glow upon an ancient tree trunk resting on the dry, dusty grounds of the Salar de Atacama. This captivating journey through the night skies concludes before the break of dawn, offering a glimpse into the celestial marvels that are woven into the nocturnal tapestry of San Pedro de Atacama.
Credit: Uwe Reichert/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)