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Twilight. Twilight is the time period between dawn and sunrise, or between sunset and dusk. Morning twilight: astronomical, nautical, and civil stages at dawn. The apparent disk of the Sun is shown to scale. [1] Evening twilight: civil, nautical, and astronomical stages at dusk. The solar disk is shown to scale.
Blue hour. The blue hour (from French l'heure bleue; [1][a] pronounced [lœʁ blø]) is the period of twilight (in the morning or evening, around the nautical stage) when the Sun is at a significant depth below the horizon. During this time, the remaining sunlight takes on a mostly blue shade. This shade differs from the colour of the sky on a ...
Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the appearance of indirect sunlight being scattered in Earth's atmosphere, when the centre of the Sun 's disc has reached 18° below the observer's horizon. [1] This morning twilight period will last until sunrise (when the Sun's upper limb breaks the ...
Sky brightness refers to the visual perception of the sky and how it scatters and diffuses light. The fact that the sky is not completely dark at night is easily visible. 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 ...
Dusk is the darkest part of evening twilight. The time of dusk is the moment at the very end of astronomical twilight, just before the minimum brightness of the night sky sets in, or may be thought of as the darkest part of evening twilight. [4] However, technically, the three stages of dusk are as follows: At civil dusk, the center of the Sun ...
Polar night and Aurora australis at the South Pole, Antarctica. Civil polar twilight in Naryan-Mar, Russia. Polar night is a phenomenon that occurs in the northernmost and southernmost regions of Earth when the Sun remains below the horizon for more than 24 hours. This only occurs inside the polar circles. [1]
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.
Look up crepuscular ray in Wiktionary, the free dictionary. Crepuscular rays or god rays are sunbeams that originate when the Sun appears to be just above or below a layer of clouds, during the twilight period. [1] Crepuscular rays are noticeable when the contrast between light and dark is most obvious. Crepuscular comes from the Latin word ...