Questions tagged [ecliptic]

Questions regarding the plane containing the orbit of the Earth around the Sun.

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How did the ancients know the constellation in which the sun is located?

The zodiac constellations lie along the plane of the ecliptic. In Spring equinox, sun lies in Pisces constellations. So Pisces is not visible during the day (because the sun light) and not visible in ...
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What is the size of the universe? [duplicate]

Will as a result of the continuation of technological progress in the twenty-first century more perfect telescopes or other astronomical instruments that will allow to know what is on the surface of ...
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Does the ecliptic plane change relative to the galactic plane?

The equatorial plane moves over time with respect to the plane of the ecliptic (that's precession!). The ecliptic is at an angle with the galactic plane, but does this angle change over time? Does the ...
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Questions on apparent motion of superior planets

Question Why is it that superior planets seem to oscillate up and down of the ecliptic, from the view of an observer on Earth, with a period equal to the planet's orbital period? Additionally, why do ...
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What is the period of the 'cycle' of Earth's ecliptic variation, relative to the 'invariable plane'? 70,000 or 100,000 years?

The plane of Earth's path around the Sun, the ecliptic, is different from the average of the solar system's as a whole (the invariable plane) by about 1.57°.... Our path around the Sun, though, goes ...
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Solar Azimuth angle Derivation

I tried posting this on math stack exchange to no avail so I thought maybe it's more relevant here : I know a similar question has been posted here before but no links to any mathematical derivations ...
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How to find the local azimuth of the highest point of the ecliptic

I would like to use pyephem or skyfield1 to find the degree of the local horizon (starting from South = 0°) at which is located the highest point of the ecliptic. Note that I am not trying to find the ...
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Launch windows for Venus transit; how to convert heliocentric longitudes to date?

Being a bit familiar with celestial mechanics, I know that the Hohmann transfer orbit is the quickest way to transfer between two circular orbits of different radii around a central body in the same ...
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Which way does the Earth tilt? [closed]

On which side does the earth tilt to? I have tried figuring it out myself but I can't seem to find the answer.
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Converting orbital elements from equatorial reference frame to ecliptic

I have a bunch of orbital elements (inclination, longitude of the ascending node, mean anomaly, argument of periapsis) that are all referenced from an equatorial reference frame. But the program I am ...
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Orientation of local star map

This image depicts our solar neighborhood Source The plane defined by the concentric circles, does it have a relationship to any galactic reference points or the ecliptic?
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Why does east and west appear to be mirrored in the celestial sphere?

I'm wondering why East is left and West on the right of the celestial sphere if you look at images of it? Example below: (source)
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How to tell which of the ecliptic cross horizon angles is to the east?

Jean Meeus' Astronomical Algorithms, 2nd ed. p. 99 gives a formula for finding the two longitudes where the ecliptic crosses the horizon: $$\tan\lambda = \frac{-\cos\theta}{\sin\epsilon \tan\phi + \...
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What is the opposite of the vernal point?

The equator and the ecliptic cross at two nodes. One of those nodes is the vernal point. What is the other one called?
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Why does the Sun track out a seemingly sinusoidal path on the celestial sphere?

The question arose because I wanted to understand the path of the ecliptic after reading about it here: https://community.dur.ac.uk/john.lucey/users/solar_year.html Is the sinusoidal path due to ...
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Where and when will someone on Earth be standing with the floor parallel to the Ecliptic plane?

I have been trying to figure this out and I think the answer might be - once per day for anyone living on the Tropic of Cancer or Capricorn. Is that right? To be clear - I want to know where on Earth ...
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Sun and moon's orbit in ecliptic coordinates using skyfield

I am new to using skyfield, is there any doc or help file that can show me on how to get the orbit of Sun and moon in ecliptic coordinate for a particular date and ...
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Orbits of planets in ecliptic coordinates

Is it possible to get the ecliptic coordinates of orbits of planets for a specific date and time? Does the ephemeris data of planets help in constructing that? Any help on this would be helpful. I ...
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Ecliptic line plot in a map

Is there any url that can give me data of ecliptic line that i can plot in a map. i.e i need earth's latitude and earth's longitude of ecliptic line for a specific time and date. Right now i only ...
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Ecliptic line data [duplicate]

I would like to get the data of ecliptic line with respect to celestial equator for a particular day. Is there any specific URL that can give me this. I only have data for declination of Sun and the ...
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How do you draw the ecliptic on a celestial sphere sketch?

I don't really understand how it's drawn on sketches of the celestial sphere. At first I thought it goes through east and west, but it does not. How do you know where to draw it? Example from Roy and ...
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Can Eight Retrograde (seen from Earth) planets occur?

First of all, for the purposes of this question Pluto is a planet. So the eight planets being considered are Mercury, Venus, Mars, Jupter, Saturn, Uranus, Neptune and Pluto. My question is: can all ...
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Why is the equinoxes only 2 days and not more?

The earth is tilted at 23.5 degrees which means that in the solstices the north/south hemisphere is more radiated by the sun and the tilt to the sun is maximum. In the equinoxes, the tilt is not ...
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Is the equinox Sun always at the same zodiac sign in the ecliptic belt?

During the year the Sun moves along the ecliptic passing all the signs of the zodiac belt, in my understanding. This means that it takes ~1 month to go from one zodiac sign to the next. The ...
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Why does moon's highest altitude change during the year

I came across a question in which moon's highest altitude had to be calculated as seen from a certain latitude, also the month and the hour and the constellation in which moon would be in had to be ...
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Recreating Observer Ecliptic Lat/Lon from JPL Horizons using SPICE toolkit

I apologise if this is the wrong place to ask. I am trying to recreate part of the calculations by the JPL Horizons system using SPICE. Specifically the Observer Ecliptic Latitude and Longitudes. I'd ...
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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 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): In ...
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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 ...