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Questions tagged [ecliptic]

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Did Eudoxus describe the eclipitic on his sun motion model?

In the description of Eudoxus’s model for the sun he says one the three circles which describe solar motion is “the circle which runs along the middle of the zodiac”. Does this refer to the ecliptic ...
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What is the great (platonic?) year? How could it be explained in laymen's terms?

How could a great year be explained in laymen's terms? According to the definition in NASA's Aerospace Dictionary it is a complete cycle of the equinoxes around the ecliptic that completes in 26000 ...
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What is meant by sun's path through zodiac

I read somewhere that sun's daily course and complete cycle is visible in the ecliptic belt by zodiac constellations. I didn't understand what that means closest I could find online is: https://www....
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Why is there free magnesium in the ecliptic (if there is) and why would some be orbiting within the ecliptic plane but retrograde?

This answer to the question What direct or indirect observations of dust can one make by eye or with binoculars? mentions Brian May's thesis and it's connection to Zodical Light: Brian May (CBE): ...
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location of the sun on the celestial sphere

The Sun, in its apparent motion along the ecliptic through the year, passes over the background of distant stars. However, given that we can't observe those stars due to the brightness of the Sun, how ...
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Moon inclination

The Moon is inclined to the ecliptic 5.15 degrees, and the equator of the Earth tilts 23.44 degrees. Since the Moon's ascending node to the ecliptic rotates, the Moon's inclination to the Earth's ...
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What does Ptolemy mean by “a line drawn from the centre of the earth through the centre of the moon to a point on the ecliptic”

This is from a translation of Ptolemy's Almagest Hence it necessarily follows that the straight line draw n from the centre of the earth (which is the centre of the ecliptic) through the centre of ...
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Why do some solar eclipses' umbra cross arctic/antarctic regions?

The ecliptic (Earth's orbital plane) is inclined 23.4 degrees. This is the same as Earth's axial tilt. The Moon's orbit is inclined 5.145 degrees to the ecliptic. Therefore, the maximum latitude ...
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360 degree equirectangular projection of all naked eye stars with precessional motion for simulating

For many years now I've been using Voyager sky simulator by Carinasoft. The projection selections are great, but Equirectangular doesn't seem to one one of them. Is there a program out there that does ...
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How did the Ancients understand the ecliptic using the Ptolemaic system

I studied the Farnese Atlas and I wonder how did the Ancients discover the ecliptic, the equator, etc. with the Ptolemaic system namely without knowing that the Earth rotates on itself, especially for ...
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Does the Earth ever cross the Moon's path with respect to the CMB?

Title says it, really. As I understand, our total peculiar motion with respect to the CMB is 631 (+/-20) km/h, in the direction of 10.5h RA; -24 deg Dec (or rather away from 22.5h RA; +24 deg Dec, ...
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What's the name of the point where you are closest or furthest from the ecliptic?

Every 24 hour day, there is a point as the earth rotates about its axis, where a location on earth is the closest to the ecliptic and where it's the furthest. Do those two points have a name? What I ...
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How does the earth's plane of orbit (ecliptic) vary over time?

Does the earth's orbital plane change with time relative to the distant stars? Does the Sun follow the same path through the zodiac (ignoring proper motions of the zodiacal stars)?
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Does the ecliptic precess? Does the Sun's rotation precess?

We know that the Earth, like a top, slowly precesses as it rotates. We know the Sun rotates, but does it precess as well? What about planetary orbits? Is the orientation of the ecliptic stable or will ...
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How to get the axial tilt vector(x,y,z) relative to ecliptic

According to the orbital plane XYZ, I understand that the axial tilt is the angle between the planet axis rotation and any normal of the plane (actually Z in right handed system). BUT, this is not ...
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Why is the Lunar Node in a daily motion?

I've read a lot about the Lunar Nodes online (on Wikipedia, astro.com and a bunch of other websites), but there is one thing I cannot figure out and the sources don't seem to clearly explain: why are ...
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Oscillation in tilt of the solar system

I know that the solar system is tilted 62.6° to the plane of the galaxy. I'm curious whether this angle changes over time, and what are the extents and time frame of any such oscillations if they ...
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Why did Mercury not appear to transit through the middle of the sun?

Why did Mercury not appear to transit through the middle of the sun (the equator)? I initially thought that this was because of the ecliptic, but, then I thought that actually we'd see it above the ...
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What visible star is closest to the ecliptic?

If we were to project the ecliptic out as an infinite plane, what visible star (besides the sun) would lie closest to it?
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Longitude of the Ecliptic

I originally went to math.stackexchange.com and they suggested I try here as well. I'm trying to figure out how to calculate times of moonrise and moonset for a given position on the earth on a ...
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Which moons have cold traps? (i.e. low ecliptic inclination in orbital and rotational axes)

Both the Moon and Mercury have polar cold traps in polar craters, with signs of volatiles. This is of course not as interesting on a moon in the outer Solar System which consists of volatiles anyway. ...
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What constellations touch the 9-degree wide Zodiac?

Say Barry, could you abuse the answer-your-own-question feature of this site, and answer the following question: As noted in How many constellations in the Zodiac? the ecliptic itself touches 13 ...