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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's disc goes 6° below the horizon in the ...
Twilight occurs according to the solar elevation angle θ s, which is the position of the geometric center of the Sun relative to the horizon. There are three established and widely accepted subcategories of twilight: civil twilight (nearest the horizon), nautical twilight, and astronomical twilight (farthest from the horizon).
In the case of alpenglow, which is similar to the Belt of Venus, [7] afterglow is used in general for the golden-red glowing light from the sunset and sunrise reflected in the sky, and in particularly for its last stage, when the purple light is reflected. [2] [1] The opposite of an afterglow is a foreglow, which occurs before sunrise ...
Anticrepuscular rays, or antisolar rays, [1] are meteorological optical phenomena similar to crepuscular rays, but appear opposite the Sun in the sky. Anticrepuscular rays are essentially parallel , but appear to converge toward the antisolar point , the vanishing point , due to a visual illusion from linear perspective .
Loosely, the term crepuscular rays is sometimes extended to the general phenomenon of rays of sunlight that appear to converge at a point in the sky, irrespective of time of day. [ 3 ] [ 4 ] A rare related phenomenon are anticrepuscular rays which can appear at the same time (and coloration) as crepuscular rays but in the opposite direction of ...
[1] [2] During these times, the brightness of the sky matches the brightness of streetlights, signs, car headlights and lit windows. The period of time shortly before the magic hour at sunrise, or after it at sunset, is called the "blue hour". This is when the sun is at a significant depth below the horizon, when residual, indirect sunlight ...
Solar ray 1 is the lowest from the Sun – the Sun is set. Solar ray 2 is reflected in the (snow) clouds to the observer. Alpenglow (from German: Alpenglühen, lit. 'Alps glow'; Italian: enrosadira) is an optical phenomenon that appears as a horizontal reddish glow near the horizon opposite to the Sun when the solar disk is just below the horizon.
Zodiacal light seen behind the Submillimeter Array from the summit of Mauna Kea. In the mid-latitudes, the zodiacal light is best observed in the western sky in the spring after the evening twilight has completely disappeared, or in the eastern sky in the autumn just before the morning twilight appears.