Atmospheric Optical Phenomena
Atmospheric Optical phenomena are caused when light from the Sun or Moon interacts with elements in the air or atmosphere, and an observer detects the light after it has interacted with those elements. Often, the light emitted by the Sun or Moon will be scattered, reflected or refracted by the elements before it reaches the observer's eyes.
Some of these events can easily fall into other categories, such as rainbows.
22 Degree Halos. Large, beautiful circles that appear around the Sun or Moon if the right conditions are present in the atmosphere. Light from the Sun and Moon can be refracted off of ice crystals at high altitudes if the crystals are present, and then detected by the eye.
Aurora. Resulting from solar particles entering Earth's atmosphere near the north and south poles, these beautiful phenomena can typically only been seen near the arctic circles.
Belt of Venus. A pink or red band that sits approximately 10 degrees above the eastern horizon right after the Sun sets in the west, or 10 degrees above the western horizon before Sun rises in the east. The pink band rests on top of a darker grey or blue band which is the Earth's shadow.
Green Flashes. An almost mythical phenomena that results when green in the light spectrum is refracted in the atmosphere as the Sun sets or rises. It lasts only seconds, and those who see it are said to be lucky.