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Why is it still considered twilight when the sun is already 15 degrees below the horizon?
Wiki User
∙ 10y ago
There is still light reflecting off the earth's atmosphere after sunset. Officially, twilight ends at 18 degrees below horizon, when it is completely dark, although at 15 degrees it is dark enough!
Wiki User
∙ 10y ago
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What is the vertical angle at solar noon?
33 degrees perpendicular to the horizon
How many degrees has the sun moved below the horizon after 22 minutes?
The Sun advances 15 degrees an hour; that is, 15 degrees every 60 minutes. You can base your calculations on that. If you live near the equator, after sunset the Sun will move directly downwards; if you live at higher latitudes, for example in Europe, the Sun moves at an angle, so while it will still move (for example) 15 degrees in an hour, it will not be 15 degrees below the horizon.
How long is a 5 foot person's shadow in a 40 degrees angle?
If the sun is 40 degrees above the horizon, a 5-ft person casts a shadow 5ft 11.5in long (rounded)
Is the sun particularly high in the sky at noon if it lies 63 degrees above the observer's horizon?
It is not particularly high but it may be the highest that it can get - depending on the observer's latitude.
What does on the horizon mean?
The "horizon" is the furthest you can see. "On the horizon" therfore refers to an object which is just in sight.
When the sun is nine degrees below the horizon which phase of twilight is it?
The sun being nine degrees below the horizon indicates that it is in the civil twilight phase. At this point, there is still enough light for most outdoor activities without the need for artificial lighting.
What is the meaning of Twilight?
Twilight is when the sun is below the horizon- either has not yet risen, or has just set. Civil twilight- what most people mean when they say twilight- the sun is no more than 6 degrees below the horizon. There is also nautical twilight, where the sun can be as much as 12 degrees below the horizon. That time is used by sailors to take "sightings" on stars with a sextant for navigation. In Nautical twilight, you can see stars, but there is still a visible horizon to use in your sightings.
What is the meaning of 'Civil' Twilight?
Twilight is when the sun is below the horizon- either has not yet risen, or has just set. Civil twilight- what most people mean when they say twilight- the sun is no more than 6 degrees below the horizon. There is also nautical twilight, where the sun can be as much as 12 degrees below the horizon. That time is used by sailors to take "sightings" on stars with a sextant for navigation. In Nautical twilight, you can see stars, but there is still a visible horizon to use in your sightings.
What is the difference between astronomical twilight and night?
When the Sun is 18 degrees below the horizon.
How can you tell the difference between astronomical twilight and night?
Astronomical twilight is the period when the sun is between 12 and 18 degrees below the horizon, resulting in a dark blue sky with no sunlight. Night follows astronomical twilight, when the sun is more than 18 degrees below the horizon and the sky is completely dark with no sunlight.
How many twilights are they and what are they called?
There are three different types of twilight: civil twilight, nautical twilight, and astronomical twilight. Civil twilight occurs when the sun is between 0 to 6 degrees below the horizon, nautical twilight occurs when the sun is between 6 to 12 degrees below the horizon, and astronomical twilight occurs when the sun is between 12 to 18 degrees below the horizon.
Why do you have to be within 48.5 degrees of the equator to get dark skies - without twilight - all year round?
The definition of "astronomical twilight" is when the Sun is more than 18 degrees below the horizon. At latitudes above 48.5 degrees, the Sun is less than 18 degrees below the horizon, even looking straight north (or south, for the southern hemisphere) at midnight on the solstice.
Is the sun considered to be low in the sky when it is 56 degrees above the horizon?
No, 56 degrees above the horizon isn't "low". "Low in the sky" is less than 20 degrees elevation or so.
What is the cutoff - southernmost - latitude for astronomical dusk - start of twilight - near the summer solstice?
At the summer solstice the sun sets on the northern horizon at latitude 66.6 degrees north. At the same time astronomical twilight ends only at latitudes below 48.6 degrees north. It's 66.6 minus 18 because for astronomical twilight to end the Sun's centre must be 18 degrees below the horizon.
Does it get darker than astronomical twilight at night in any part of Denmark around the June solstice?
No. The southern border of Denmark is at 54 degrees 44 minutes north.Wikipedia sez: "Astronomical twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 18 degrees below the horizon."At midnight in the June Solstice, the Sun is at a declination of 23.5 degrees (approximately), so the over-the-pole angular distance is (90-54.5) + (90-23.5) degrees, or 102 degrees. The horizon is 90 degrees, so the Sun is 15 degrees below the northern horizon at midnight on June 21.So, no, it won't meet the definition for "darker than astronomical twilight".
Does it get darker than astronomical twilight in London England on nights near the June solstice?
Wikipedia sez: "Astronomical twilight is defined to begin in the morning, and to end in the evening when the center of the Sun is geometrically 18 degrees below the horizon." London, England is at 51 degrees north latitude. At midnight in the June Solstice, the Sun is at a declination of 23.5 degrees (approximately), so the over-the-pole angular distance is (90-51) + (90-23.5) degrees, or 105 degrees. The horizon is 90 degrees, so the Sun is 15 degrees below the northern horizon at midnight on June 21. So, no, it won't meet the definition for "darker than astronomical twilight".
Does it get darker than astronomical twilight in Newcastle-upon-Tyne England in June?
No because the latitude is 55 degrees N so the Sun never goes more than 11½ degrees below the northern horizon, so nautical twilight and astronomical twilight do not end.
