Light pillar in the context of Moonlight

Atmospheric optical phenomena include:

• Afterglow
• Airglow
• Alexander's band, the dark region between the two bows of a double rainbow.
• Alpenglow
• Anthelion
• Anticrepuscular rays
• Aurora (northern and southern lights, aurora borealis and aurora australis)
• Belt of Venus
• Brocken Spectre
• Circumhorizontal arc
• Circumzenithal arc
• Cloud iridescence
• Crepuscular rays
• Earth's shadow
• Earthquake lights
• Glories
• Green flash
• Halos, of Sun or Moon, including sun dogs
• Haze
• Heiligenschein or halo effect, partly caused by the opposition effect
• Ice blink
• Light pillar
• Lightning
• Mirages (including Fata Morgana)
• Monochrome Rainbow
• Moon dog
• Moonbow
• Nacreous cloud/Polar stratospheric cloud
• Rainbow
• Sprite (lightning)
• Subsun
• Sun dog
• Tangent arc
• Tyndall effect
• Upper-atmospheric lightning, including red sprites, Blue jets, and ELVES
• Water sky

A false sunrise is any of several atmospheric optical phenomena in which the Sun appears to have risen, but is actually still some distance below the horizon. A number of different atmospheric conditions can be responsible for this effect, all of which divert the sunlight in such a way as to allow it to reach the observer's eye, thereby giving the impression that the light comes directly from the Sun itself. The spread of light can sometimes resemble that of the true sun.

Several atmospheric phenomena that may alternatively be called a "false sunrise" are:

A false sunset can refer to one of two related atmospheric optical phenomena: (1) the Sun appears to be setting into or to have set below the horizon while it is actually still some height above the horizon; or (2) the Sun has already set below the horizon, but still appears to be on or above the horizon (thus representing the reverse of a false sunrise). Depending on the circumstances, these phenomena can give the impression of an actual sunset.

There are several atmospheric conditions which may cause the effect, most commonly a type of halo, caused by the reflection and refraction of sunlight by small ice crystals in the atmosphere, often in the form of cirrostratus clouds. Depending on which variety of "false sunset" is meant, the halo has to appear either above the Sun (which itself is hidden below the horizon) or below it (in which case the real Sun is obstructed from view, e.g. by clouds or other objects), making the upper and lower tangent arcs, upper and lower sun pillars and the subsun the most likely candidates.

A halo (from Ancient Greek ἅλως (hálōs) 'threshing floor, disk') is an optical phenomenon produced by light (typically from the Sun or Moon) interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Many of these appear near the Sun or Moon, but others occur elsewhere or even in the opposite part of the sky. Among the best known halo types are the circular halo (properly called the 22° halo), light pillars, and sun dogs, but many others occur; some are fairly common while others are extremely rare.

The ice crystals responsible for halos are typically suspended in cirrus or cirrostratus clouds in the upper troposphere (5–10 km (3.1–6.2 mi)), but in cold weather they can also float near the ground, in which case they are referred to as diamond dust. The particular shape and orientation of the crystals are responsible for the type of halo observed. Light is reflected and refracted by the ice crystals and may split into colors because of dispersion. The crystals behave like prisms and mirrors, refracting and reflecting light between their faces, sending shafts of light in particular directions.