Caption: 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.
Credit: Giorgia Hofer/IAU OAE

Caption: 這張令人歎為觀止的照片是 2020 年 6 月 25 日在印度尼西亞西爪哇庫寧安省西里穆斯市凌加梅卡村的晴朗夜空下拍攝的，照片中的星軌掠過南半球的天際。星軌是地球自轉所導致的恆星表觀運動，當長時間跟蹤時，就會產生這些令人著迷的光弧。因為這張照片是在赤道附近拍攝的，所以恆星所圍繞旋轉的點（南天極）靠近地平線。攝影師使用智能手機上的星軌功能，在較長時間內拍攝了一系列圖像，並將它們疊加在一起。前景引人注目的大樹增添了畫面的深度，使上方天體的運動與地面的靜止形成了鮮明對比，同時也遮掩了周圍的一些光汙染。世界不同地區的夜空景色各異，令人驚嘆，使人們意識到保護各地黑暗天空的重要性。
Credit: Slamat Riyadi/IAU OAE (CC BY 4.0)

Caption: 這段視頻展示了銀河在茫茫星空中的璀璨光芒。在群星的大劇場中，南十字星座占據了一席之地，其獨特的十字形狀在本視頻的頂部可見，就在銀河系上方，稍微向右。隨著視頻的推進，南十字座慢慢消失在視野。這個天文記號是南半球的一個突出特徵，具有文化和導航意義，幾個世紀以來一直是航行路標。與銀河的壯觀相伴的是兩朵麥哲倫雲，它們是在遙遠天空中翩翩起舞的夥伴。船底座星雲為宇宙全景增添了空靈縹緲的光輝，在黑暗中描繪出一種璀璨的色調。在這場天體芭蕾中，溫和的綠色籠罩著大氣層，這種現象被稱為 "氣輝"，為夜空增添了一抹微妙的熒光。地面上也有飛機從頭頂飛過和車輛在天文臺建築之間行駛的景象。這幅延時攝影是從智利的拉西亞天文臺拍攝的，它是一扇通往迷人星舞的窗口，讓我們得以一窺銀河系令人驚嘆的美景和南天的地標。
Credit: José Rodrigues/IAU OAE (CC BY 4.0)

Caption: 這幅延時攝影作品拍攝於 2023 年 6 月從智利聖佩德羅德阿塔卡馬，展現了南十字星在夜空中壯麗的旅程，指引著南天極周圍的天空旋轉，直到它優雅地落下。滿天繁星的畫布展示了銀河的壯麗，以及圍繞南天極旋轉的大麥哲倫雲和小麥哲倫雲。顯著的星座包括十字、半人馬座、天蠍座和以前的阿爾戈船座（船尾座、帆座、船座）也都可見。整個景象在夜幕降臨後不久開始，捕捉到坎普斯星的耀眼下降，這顆明亮的星星即將沉入地平線。在序列中，可以隱約看到經過的飛機、閃爍的汽車車燈、漂浮的雲朵以及神祕的空氣輝光。在一個驚豔的時刻，一顆流星劃過天空，璀璨的火球在大約第41秒時短暫點亮畫面的右下角。隨著序列的發展，升起的月亮優雅地照亮了風景，把光輝灑在靜臥於阿塔卡馬鹽灘乾燥塵土中的古老樹幹上。這段迷人的夜空之旅在黎明前結束，提供了一瞥交織在聖佩德羅·阿塔卡瑪夜晚風景中的天體奇蹟。
Credit: Uwe Reichert/IAU OAE (CC BY 4.0)

Caption: 這段延時攝影捕捉了來自國家天體物理研究所 (INAF) 的 64 米撒丁島射電望遠鏡 (SRT) 周圍的恆星運動，特別是在天球背景下著名的北斗七星。隨著飛機飛過和射電望遠鏡旋轉，著名的北斗七星在天空中下沉，鏡頭也隨之移動。恆星的軌跡與射電望遠鏡的巨大天線之間的和諧互動，為 2019 年 9 月拍攝的宇宙芭蕾譜寫了一曲令人著迷的視覺頌歌。
Credit: Antonio Finazzi/IAU OAE (CC BY 4.0)

Caption: 這張拍攝於2022年10月的照片是在印度阿馬爾提亞村（Amartiya）帕諾提耶（Panotiya）的黑夜中拍攝的，展現了夜空中美麗的星軌。攝影師僅用一部智能手機和一個三腳架就捕捉到了這些星軌——它們是我們星球自轉的視覺證據，因為每一條星軌都代表著地球自轉時恆星的明顯運動，創造出令人著迷的宇宙光影編舞。恆星有不同的顏色，有的閃著藍光，有的泛白，暗示著它們不同的溫度和組成。此外，一架飛機的細微軌跡與永恆的星空之舞短暫的交匯在一起，寧靜的星空與下方熙熙攘攘的生命活動形成了鮮明對比。
Credit: Govind Gurjar/IAU OAE (CC BY 4.0)

Caption: 北斗七星優雅地移動於加利福尼亞州莫諾湖超凡脫俗的凝灰岩層之上。延時攝影捕捉了北斗七星穿過北方地平線直至下合的過程。在莫諾湖的緯度（+38°）上，北斗七星的星星幾乎都是環極星，除了阿爾凱德（Alkaid）。北極星位於地平線之上38°的位置，正好在視野的右上角之外。月光將大地籠罩在柔和的光暈中，隨著月亮落下，光暈逐漸變暗，整個場景陷入黑暗之中。
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)