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  2. Night sky - Wikipedia

    en.wikipedia.org/wiki/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. Natural light sources in a night sky include moonlight, starlight, and airglow, depending on location and timing. Aurorae light up the skies above the ...

  3. Astronomical clock - Wikipedia

    en.wikipedia.org/wiki/Astronomical_clock

    It has a concentric dial showing the 24-hour time, the date and zodiac, and the moon phase, and a star map dial with a dragon hand, and indicates the time of sunrise and sunset. [19] Třebíč. At the Třebíč Astronomical Observatory, a modern astronomical clock which shows the time in world cities, the time of sunrise and sunset, the date ...

  4. Moonrise and moonset - Wikipedia

    en.wikipedia.org/wiki/Moonrise_and_moonset

    Moonrise and moonset are times when the upper limb of the Moon appears above the horizon and disappears below it, respectively. The exact times depend on the lunar phase and declination, as well as the observer's location. As viewed from outside the polar circles, the Moon, like all other celestial objects outside the circumpolar circle, rises ...

  5. Betelgeuse - Wikipedia

    en.wikipedia.org/wiki/Betelgeuse

    Betelgeuse is the brightest near-infrared source in the sky with a J band magnitude of −2.99; [95] only about 13% of the star's radiant energy is emitted as visible light. If human eyes were sensitive to radiation at all wavelengths, Betelgeuse would appear as the brightest star in the night sky.

  6. Atmospheric refraction - Wikipedia

    en.wikipedia.org/wiki/Atmospheric_refraction

    Diagram showing displacement of the Sun 's image at sunrise and sunset. Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. [1] This refraction is due to the velocity of light through air decreasing ...

  7. Sunrise - Wikipedia

    en.wikipedia.org/wiki/Sunrise

    Sunrise seen over the Atlantic Ocean through cirrus clouds on the Jersey Shore at Spring Lake, New Jersey, U.S. Sunrise (or sunup) is the moment when the upper rim of the Sun appears on the horizon in the morning. [1] The term can also refer to the entire process of the solar disk crossing the horizon.

  8. Sky brightness - Wikipedia

    en.wikipedia.org/wiki/Sky_brightness

    If light sources (e.g. the Moon and light pollution) were removed from the night sky, only direct starlight would be visible. The sky's brightness varies greatly over the day, and the primary cause differs as well. During daytime, when the Sun is above the horizon, the direct scattering of sunlight is the overwhelmingly dominant source of light.

  9. Sunrise equation - Wikipedia

    en.wikipedia.org/wiki/Sunrise_equation

    Sunrise equation. A contour plot of the hours of daylight as a function of latitude and day of the year, using the most accurate models described in this article. It can be seen that the area of constant day and constant night reach up to the polar circles (here labeled "Anta. c." and "Arct. c."), which is a consequence of the earth's inclination.