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If you were to take a photograph of the Sun at noon each day, without moving the camera even a whisker, the daily path that the Sun would appear to take is a figure-8 pattern called an "analemma".
Wiki User
∙ 14y ago
Wiki User
∙ 10y agoAn analemma is the figure formed in the sky by the Sun's position at a particular time of day over the course of a year. It's figure-8 shaped.
It is caused by 2 things:
1) The apparent north-south motion of the Sun in the sky during a year, caused by the tilt of the Earth's axis. (This is the main reason we have the "seasons".)
2) The difference between "clock time" and "sundial time".
In effect, clocks average out the variations in the Sun's apparent daily motion across the sky during a year, sundials show up these variations.
This particular difference is because of 2 completely separate effects:
a) the Earth's tilt, again.
b) the Earth's elliptical (rather than circular) orbit.
Wiki User
∙ 10y agoI assume you know already what the analemma is.
Its typical "figure-of-eight" shape is caused by 2 things:
1) The apparent seasonal movement of the Sun in the sky (north-south) during the year.
2) The difference, during a year, in the positions of the "True Sun" and the "Mean Sun" during the Sun's daily path across the sky.
The True Sun is what a sundial uses to measure time.
The Mean Sun is what clocks use (more or less).
The Mean Sun averages out the little variations in the position of the Sun during the year.
The variations of the True Sun are caused by the Earth's non-circular (elliptical) orbit and by the Earth's tilted axis.
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Shape of the analemma if the ecliptic-equator angle increases?
The analemma would stretch in the north-south dimension.
How does the analemma relate to the motion of the sun along the ecliptic?
The Sun is always on the ecliptic, even though the analemma seems to suggest that the Sun is engaged in some kind of fancy wobble. The analemma has a "figure of eight" shape. There are two components that cause this shape. First, the Sun seems to move in the north-south direction in the sky during the year, because of Earth's tilted axis. The second component is explained below. This is about the Sun's apparent daily motion East to West across the sky: The analemma is also caused because civil time or Universal Time (UTC) does not line up perfectly with "apparent solar time". Apparent solar time is what a sundial measures. UTC is almost exactly the same as "mean solar time" (the original "Greenwich Mean Time"). Our clocks are based on UTC. UTC gives the average day length over the course of a year, independent of the exact position of the Sun in the sky. The difference between these two measurements of time is caused by the Earth's tilt (again) and the Earth's elliptical orbit. So the analemma captures the Sun sometimes earlier than, and sometimes later than, what would be the theoretical 'average' position of the Sun (sometimes called "Mean Sun") over the course of a year. The analemma doesn't actually 'exist' as a physical reality. For those who are not familiar with the term, this is how you would 'observe' the analemma. Set up a camera in such a way that it will capture an image of the Sun at, for example, exactly 12:00 noon, in your local timezone. Keep the camera firmly anchored and under enough protection so that it can remain where it is for an entire year. At regular weekly intervals photograph the Sun at exactly 12:00 noon. At the end of the year, the image will show the characteristic "8" shape of the analemma. The one thing you will have to do is assure that the initial camera's view is such that the Sun will always appear in the image at noontime, all year. If you start with the Sun exactly in the middle, there may be a season when the Sun at noon will not be in the camera's view. Also you need to allow for "daylight saving" changes to your local noon, of course.
Describe the suns change of position in the sky during 1 year?
There is an exact word for this phenomenon, an analemma. This is an asymmetric figure-of-eight, somewhat skinny, and would be the shape composed if you marked the position of the sun at the same time each day throughout the year. The actual asymmetry of the figure-of-eight varies with latitude, and reverses completely by the time you travel to the other arctic (or antarctic) circle.
Name 10 artificial sources of light?
1. The sun 2. the sun 3. the sun 4. the sun 5. the sun 6. the sun 7. the sun 8. the sun 9. the sun 10. the sun
What instrument was sun sun good at in the book my father sun sun Johnson?
WHAT INSTURMENT DOES MY FATHER SUN SUN JOHNSON
What is an analemma?
An analemma is an egg-shaped or figure-eight curve which results when the sun's position in the sky is plotted over the course of the year at the same hour of mean solar time every day.
Shape of the analemma if the ecliptic-equator angle increases?
The analemma would stretch in the north-south dimension.
How does the analemma relate to the motion of the sun along the ecliptic?
The Sun is always on the ecliptic, even though the analemma seems to suggest that the Sun is engaged in some kind of fancy wobble. The analemma has a "figure of eight" shape. There are two components that cause this shape. First, the Sun seems to move in the north-south direction in the sky during the year, because of Earth's tilted axis. The second component is explained below. This is about the Sun's apparent daily motion East to West across the sky: The analemma is also caused because civil time or Universal Time (UTC) does not line up perfectly with "apparent solar time". Apparent solar time is what a sundial measures. UTC is almost exactly the same as "mean solar time" (the original "Greenwich Mean Time"). Our clocks are based on UTC. UTC gives the average day length over the course of a year, independent of the exact position of the Sun in the sky. The difference between these two measurements of time is caused by the Earth's tilt (again) and the Earth's elliptical orbit. So the analemma captures the Sun sometimes earlier than, and sometimes later than, what would be the theoretical 'average' position of the Sun (sometimes called "Mean Sun") over the course of a year. The analemma doesn't actually 'exist' as a physical reality. For those who are not familiar with the term, this is how you would 'observe' the analemma. Set up a camera in such a way that it will capture an image of the Sun at, for example, exactly 12:00 noon, in your local timezone. Keep the camera firmly anchored and under enough protection so that it can remain where it is for an entire year. At regular weekly intervals photograph the Sun at exactly 12:00 noon. At the end of the year, the image will show the characteristic "8" shape of the analemma. The one thing you will have to do is assure that the initial camera's view is such that the Sun will always appear in the image at noontime, all year. If you start with the Sun exactly in the middle, there may be a season when the Sun at noon will not be in the camera's view. Also you need to allow for "daylight saving" changes to your local noon, of course.
Is a analemma useful only north of the tropic of Capricorn?
No, an analemma is not limited to only north of the Tropic of Capricorn. An analemma is a figure-eight shape that represents the Sun's position in the sky at the same time each day throughout a year. It can be observed anywhere on Earth, as long as there are daily changes in the Sun's position relative to the observer.
What is the thing that looks like a stretched out 8 on a globe called?
It is called the analemma. It describes the apparent change in position of the sun that results from the tilt in earth's axis, and the libration caused by earth's changing velocity in its orbit around the sun.
Is the analemma is a useful tool for locations north of the Tropic of Capricorn?
Yes
Does the sun rise at the same time?
No, the time of sunrise varies throughout the year. If you look up "Equation of Time" and "Analemma" in a search engine you'll be well informed. The day on which sun rises the earliest is NOT the same day upon which it sets the latest! And similarly for mid-winter.
Does the analemma determine how far a country is located from the equator?
If it is on a map or globe, then yes, it does.
What two things does the analemma show?
The solar analemma is an elongated figure of eight. There are three main parameters which define the shape - obliquity, eccentricity and the angle between the apse line and the line of solstice. The distance from the node, along the north-south lobes show the latitude [on Earth] at which the sun is overhead. This is a measure of the earth's axial tilt.The distance from the vertical axis - in the east-west direction - is a measure of the difference between the time as shown by the sun's position and clock time. This is a measure of the eccentricity of the earth's orbit.
What if earth moved in a circular orbit farther from the sun?
It would be colder on Earth. the farther, the colder. Also solar time and civil time would match up perfectly or nearly so; there would be no need for a 'mean solar day', or 'mean time'. The analemma would be a straight line.
How does the daily path of the sun across the sky change with the season?
The Sun's path in the sky will appear to change as a year passes. This path resembles a figure eight. The path is curved due to Earth's tilted axis. The path is long because the Earth makes an oblong orbit around the Sun. The path is technically called a Analemma. The movement of the sun isn't what causes the change of seasons on earth. It is the movement of the earth around the sun and the fact that the axis of rotation of the earth is not perpendicular to the plane of solar rotation that gives rise to the changes we see as the seasons.
How do you make a Loop Sundial and use its equations?
I think the magic word here is Analemma and you'll find a wikipedia article of good quality.
