Atmospheric halos are a light scattering phenomenon caused by airborne ice crystals in the atmosphere. Halos can be seen by the naked eye. They provide the observer the information on the kinds of ice crystals present in the sky during a halo display. A combination of ice crystals’ shape, their orientation, and light ray paths through the crystals dictates what halos will be observable. All well-known halos are produced by the interaction of light with crystals of hexagonal water ice. However, some of the documented halos cannot be explained using common hexagonal ice crystals. It might be required to consider such factors as abnormal crystal shape, crystals of cubic water ice, or airborne crystals of other minerals to explain the nature of some exotic halos.

Halos can be also observed in the atmospheres of other planets or their moons, which provides information on airborne ice crystals or crystals of other minerals. Ice crystal halos have been already photographed in the Martian atmosphere.

In this article, we summarize the current knowledge of atmospheric halos and show which halo forms cannot be explained by ordinary hexagonal ice crystals. We list here 119 different identifiable halo forms known by today.

大气晕是由大气中空气中的冰晶引起的光散射现象。肉眼可以看到光晕。它们向观察者提供有关光晕显示期间天空中存在的冰晶种类的信息。冰晶的形状、它们的方向和穿过晶体的光线路径的组合决定了可以观察到的光晕。所有众所周知的光晕都是由光与六角形水冰晶体的相互作用产生的。然而，一些记录在案的光晕无法使用常见的六角冰晶来解释。可能需要考虑异常晶体形状、立方水冰晶体或其他矿物的空气晶体等因素来解释一些奇异光晕的性质。

在其他行星或其卫星的大气中也可以观察到光晕，这提供了有关空中冰晶或其他矿物晶体的信息。已经在火星大气中拍摄到冰晶晕。

在这篇文章中，我们总结了当前关于大气晕的知识，并展示了普通的六边形冰晶无法解释的晕形式。我们在这里列出了今天已知的 119 种不同的可识别光环形式。