2024年12月25日

Diamond Dust Sky Eye
Image Credit & Copyright: Jaroslav Fous

Explanation: Why is there a huge eye in the sky? Diamond dust. That is an informal term for small ice crystals that form in the air and flitter to the ground. Because these crystals are geometrically shaped, they can together reflect light from the Sun or Moon to your eyes in a systematic way, causing huge halos and unusual arcs to appear. And sometimes, together the result can seem like a giant eye looking right back at you. In the featured image taken in the Ore Mountains of the Czech Republic last week, a bright Moon rising through ice fog-filled air resulted in many of these magnificent sky illusions to be visible simultaneously. Besides Moon dogs, tangent arcs, halos, and a parhelic circle, light pillars above distant lights are visible on the far left, while Jupiter and Mars can be found just inside the bottom of the 22-degree halo.

Your Sky Surprise: What picture did APOD feature on your birthday? (post 1995)
Tomorrow’s picture: grand spiral galaxy

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钻石尘天眼
影像提供与版权: Jaroslav Fous

说明: 为什么天空中悬着一只巨眼？答案是因为有钻石尘。在气象学里，钻石尘是漂浮在空中并缓慢飘落的小冰晶之俗名。由于这类冰晶具有特定的几何形状，可以系统性的反射来自太阳或月亮的光，从而在天空中形成巨大的光晕及不寻常的光弧。有时候，这种大气光学现象可造就看似在凝视众生的巨眼。在这幅上星期摄于捷克 奥雷山脉的影像里，来自东升明月的光穿过地表上方的冰雾，产生了多种壮观的天空幻景。其中除了幻月、正切弧、月晕，幻月环、及左侧远处灯火上方的光柱之外，还可见到22度晕下缘内侧的木星和火星。（22-degree halo 22度晕；infralateral arc 下虹弧；Moon dog 幻月; parhelic circle 幻日环/幻月环；tangent arc 正切弧 ）

你的天空惊喜: 你生日那天APOD展示了什么照片？（1995年后）
明日的图片: open space