2026年1月9日
Ice Halos by Moonlight and Sunlight
Image Credit & Copyright: Antonella Cicala
Explanation: Both Moon and Sun create beautiful ice halos in planet Earth’s sky. In fact, the two brightest celestial beacons are each surrounded by a complex of ice halos in these photos of the sky above Chamonix-Mont-Blanc in France. The panels were recorded one night (left) and the following day at the end of December 2025. Similar ice halos appear in moonlight and sunlight because they are all formed through the geometry of flat, hexagonal ice crystals. The ice crystals reflect and refract light as they flutter in the cold atmosphere above the mountain resort. In the pictures both Moon and Sun are surrounded by a more commonly seen 22 degree circular halo. Bright and sometimes colorful patches at the intersections of the 22 degree circular halos with the indicated parselenic and parhelic arcs are also known as Moon dogs and Sun dogs.
Tomorrow’s picture: opposite the Sun
月光与日光下的冰晕现象
影像提供与版权: Antonella Cicala
说明: 月亮和太阳都会在地球天空中形成美丽的冰晕。事实上，在这些拍摄于法国霞慕尼勃朗峰上空的照片中，最明亮的两颗天体都被复杂的冰晕所环绕。这些照片分别拍摄于2025年12月底的一个夜晚（左图）和第二天。类似的冰晕现象在月光和阳光下都会出现，因为它们都通过扁平六角形冰晶的几何结构形成的。冰晶在山区度假胜地上空寒冷的大气中飘动时，会反射和折射光线。在照片中，月亮和太阳都被常见的22度圆形光晕环绕。在22度圆形光晕与图中所显示的幻日环和幻月环相交处出现的明亮且有时色彩斑斓的区域，也被称为幻月（Moon dogs）和幻日（Sun dogs）。
明日的图片: opposite the Sun
