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.
1. 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.
Alpenglow is a phenomenon that is very similar to the Belt of Venus, and occurs just after sunset. The term was coined because the pink light that appears in the sky, opposite of the sunset, gives mountains a pinkish “glow”.
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.
4. 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.
5. Crepuscular Rays
Large rays of sunlight in the sky that appear to meet or converge at the Sun from an observer’s perspective. These rays of sunlight are actually parallel, but they appear to come together due to the long distances between the observer, the horizon and the Sun.
6. 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.
7. Zodiacal Light
Zodiacal light is a faint light reflected off of planets, dust and asteroid in our solar system. As these objects all lie on the same, flat plane (the ecliptic plane), the light reflected off of them can be seen under special circumstances. This phenomenon is similar to the way dust and stars in the Milky Way create a beautiful band across a dark, nighttime sky.