Questions tagged [ecliptic]
Questions regarding the plane containing the orbit of the Earth around the Sun.
53
questions
3
votes
1answer
50 views
How 3’ minute arc error in the Sun altitude might amount to 7’ minute arc displacement in Sun's longitude?
In reading "The Error in Kepler's Acronychal Data for Mars" by Curtis Wilson 1969 (unfortunately , this is not an open article), we read the following paragraph:
How did it come about that ...
1
vote
0answers
32 views
Would a telescope substantially away from the ecliptic plane improve TNO detection?
There have been lots of new TNOs found in the last decade.
Would a telescope far from the ecliptic plane be useful to image them, and spot new ones?
What about planet nine, assuming it exists: would ...
1
vote
0answers
68 views
J2000 conversion to Position of date
Having spent an inordinate amount of time comparing the LBR values of Meeus (Astronomical Algorithms 1998) vs. ELP82B (Chapront's ELP82b Fortran Program)
I have figured out the data set I'm using is ...
0
votes
1answer
37 views
Mars Ecliptic Latitude
It's stated Mars orbital plane is 1.8 degree to the ecliptic.
How then can Mars can ecliptic latitude went beyond 1.8 ?
Example; Jan 8th 2023, Mars latitude at +2.8. 24th Jan 2025, +4.3.
Isn't the ...
3
votes
1answer
592 views
Could there be an eclipse tomorrow if the Pleiades is covered by the Moon tonight?
I'm trying to solve this task:
Suppose today there is a covering of the Pleiades star cluster by the Moon. Could there be an eclipse of the sun tomorrow? The moon?
I think the answer to both is no, ...
1
vote
1answer
113 views
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 ...
1
vote
0answers
30 views
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 ...
2
votes
1answer
84 views
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 ...
4
votes
1answer
183 views
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 ...
1
vote
0answers
34 views
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 ...
2
votes
2answers
143 views
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 ...
3
votes
1answer
87 views
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 ...
1
vote
1answer
107 views
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 ...
1
vote
1answer
130 views
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.
4
votes
1answer
233 views
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 ...
3
votes
1answer
130 views
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?
1
vote
3answers
195 views
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)
2
votes
1answer
115 views
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 + \...
1
vote
0answers
79 views
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?
3
votes
3answers
465 views
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 ...
1
vote
0answers
67 views
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 ...
1
vote
1answer
248 views
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 ...
1
vote
0answers
248 views
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 ...
1
vote
1answer
183 views
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 ...
0
votes
0answers
66 views
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 ...
0
votes
2answers
1k views
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 ...
6
votes
1answer
1k views
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 ...
2
votes
4answers
503 views
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 ...
3
votes
4answers
473 views
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 ...
3
votes
1answer
808 views
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 ...
4
votes
0answers
37 views
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 ...
4
votes
0answers
69 views
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 ...
3
votes
1answer
331 views
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 ...
1
vote
2answers
370 views
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....
8
votes
1answer
159 views
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 ...
3
votes
0answers
118 views
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 ...
2
votes
1answer
892 views
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 ...
1
vote
0answers
52 views
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 ...
4
votes
1answer
159 views
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 ...
3
votes
1answer
380 views
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 ...
4
votes
4answers
1k views
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 ...
1
vote
1answer
143 views
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, ...
2
votes
1answer
113 views
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 ...
9
votes
1answer
1k views
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)?
0
votes
1answer
518 views
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 ...
4
votes
1answer
1k views
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 ...
1
vote
1answer
581 views
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 ...
4
votes
1answer
162 views
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 ...
1
vote
2answers
392 views
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 ...
1
vote
2answers
621 views
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?
