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Glossary term: 天极

Description: 南北两天极被定义为地球自转轴与天球的交点。

在地球的北极,北天极总是在正上方;而在地球的南极,南天极总是在正上方。由于地球自转,北半球的天空似乎围绕着北天极旋转,而南半球的天空似乎围绕着南天极旋转。北天极的赤纬为+90度,而南天极的赤纬为-90度。

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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher
The translation of this term and its definition is still awaiting approval

The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".

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北斗七星和新智彗星 C2020 F3

Caption: 这段延时摄影记录了2020年7月拍摄的三帧画面中标志性的北斗七星的轨迹。影像在意大利的三个地点拍摄:拉瓦雷多三峰(Tre Cime di Lavaredo)奥隆佐迪卡多雷、里特山(Monte Rite)奇比亚纳迪卡多雷,以及拉佐牧场(Casera Razzo)维戈迪卡多雷。这场视觉奥德赛展示了北斗七星的迷人轨迹,并在夜空中绘制出天体画卷。它不仅描绘了这个著名星群的轨迹,还捕捉到2020年7月照亮天空的罕见新智彗星 C/2020 F3 这一非凡的天文事件,为我们的夜空增添了光彩。
Credit: 乔尔贾·霍弗/国际天文学联合会教育办公室 (CC BY 4.0)

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繁星划出的数百条小弧线以地平线附近的一个点为中心形成同心圆。一棵树矗立在前景中。

博特尔四级光污染下的南半球星轨

Caption: 这张令人叹为观止的照片是 2020 年 6 月 25 日在印度尼西亚西爪哇库宁安省西里穆斯市凌加梅卡村的晴朗夜空下拍摄的,照片中的星轨掠过南半球的天际。星轨是地球自转所导致的恒星表观运动,当长时间跟踪时,就会产生这些令人着迷的光弧。因为这张照片是在赤道附近拍摄的,所以恒星所围绕旋转的点(南天极)靠近地平线。摄影师使用智能手机上的星轨功能,在较长时间内拍摄了一系列图像,并将它们叠加在一起。前景引人注目的大树增添了画面的深度,使上方天体的运动与地面的静止形成了鲜明对比,同时也遮掩了周围的一些光污染。世界不同地区的夜空景色各异,令人惊叹,使人们意识到保护各地黑暗天空的重要性。
Credit: Slamat Riyadi/IAU OAE (CC BY 4.0)

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The Milky Way appears as a diagonal stripe bottom left to top right. It becomes more horizontal as the video progresses.

Southern Sky Over La Silla

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)

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The Southern Cross points out the South Celestial Pole, around which the sky appears to rotate

Beautiful Night in the Atacama Desert

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Credit: Uwe Reichert/IAU OAE (CC BY 4.0)

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The dish of a radio telescope rotates as the Big Dipper moves in the sky behind.

The Big Dipper with the Sardinia Radio Telescope SRT

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Credit: Antonio Finazzi/IAU OAE (CC BY 4.0)

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The Big Dipper sinks in the sky with the handle sweeping out a larger circle than the bowl of the asterism.

Big Dipper Over the Mono Lake

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)

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Timelapses of rotating skies behind trees, telescopes, mountains and observatories

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Credit: Jianfeng Dai/IAU OAE (CC BY 4.0)

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A traditional Chinese building. Above the streaks of stars form a circular pattern around the north star.

Star Trails of the Forbidden City

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Credit: Stephanie Ziyi Ye/IAU OAE (CC BY 4.0)

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