Clear Night Sky

Night sky

The night sky is the nighttime appearance of celestial objects like stars, planets, and the Moon, which are visible in a clear sky between sunset and sunrise, when the Sun is below the horizon.

Night

Night, or nighttime, is the period of darkness when the Sun is below the horizon. Daylight illuminates one side of Earth, leaving the other in darkness. The opposite of nighttime is daytime. Earth's rotation causes the appearance of sunrise and sunset. Moonlight, airglow, starlight, and light pollution dimly illuminate night. The duration of day, night, and twilight varies depending on the time of year and the observer's latitude.

Sky

The sky is an unobstructed view upward from the surface of the Earth. It includes the atmosphere and outer space. It may also be considered a place between the ground and outer space, thus distinct from outer space.

Transparency and translucency

In the field of optics, transparency is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale, the photons can be said to follow Snell's law. Translucency is the physical property of allowing light to pass through the material. It allows light to pass through but the light does not necessarily follow Snell's law on the macroscopic scale; the photons may be scattered at either of the two interfaces, or internally, where there is a change in the index of refraction. In other words, a translucent material is made up of components with different indices of refraction, while a transparent material is made up of components with a uniform index of refraction. Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color. The opposite property of translucency is opacity. Other categories of visual appearance, related to the perception of regular or diffuse reflection and transmission of light, have been organized under the concept of cesia in an order system with three variables, including transparency, translucency and opacity among the involved aspects.

clear

Adjective

1. Transparent in colour.
2. Bright; luminous; not dark or obscured.

Adverb

1. All the way; entirely.
2. Not near something or touching it.

night

Noun

1. The time when the Sun is below the horizon when the sky is dark.
2. The period of darkness beginning at the end of evening astronomical twilight when the sun is 18 degrees below the horizon, and ending at the beginning of morning astronomical twilight.

Interjection

1. Ellipsis of good night.

sky

Symbol

1. ISO 639-3 language code for Sikaiana.

Noun

1. The atmosphere above a given point, especially as visible from the surface of the Earth as the place where the sun, moon, stars, and clouds are seen.
2. With a descriptive word: the part of the sky which can be seen from a specific place or at a specific time; its climate, condition, etc.