Ecliptic Definition and 29 Threads

The ecliptic is the plane of Earth's orbit around the Sun. From the perspective of an observer on Earth, the Sun's movement around the celestial sphere over the course of a year traces out a path along the ecliptic against the background of stars. The ecliptic is an important reference plane and is the basis of the ecliptic coordinate system.

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  1. K

    I Is the Ecliptic Plane the Same as the Apparent Path of the Sun?

    Please correct my statements: By definition, the ecliptic plane is the path of the Earth around our Sun. Beta of Earth is 0.0000. The ecliptic is very flat since Jupiter is only 0.5 degrees off the ecliptic. From Wikipedia: " The ecliptic is actually the apparent path of the Sun throughout the...
  2. K

    I Do stars in the ecliptic seasonally change brightness?

    Has any astronomer observed any seasonal changes in the brightness of stars lying close to the ecliptic plane? (Other stars are: d Cnc b=+0.08, mag.=+3.9; d Gem b=-0.18, mag.=+3.5; a Lib b=+0.33, mag.=+2.7.) Once a year these stars are occulted by the Sun. What happens from the date of...
  3. M

    A Definition of the IAU for the ecliptic plane

    How is the definition of the IAU for the ecliptic plane? In particular I am interested how the perturbations are treated. Neither the Earth nor the common gravity center of Earth and moon move on an exact plane around the sun. I found the IAU document “Adoption of the P03 Precession Theory and...
  4. thebosonbreaker

    I Confusion over what exactly constitutes the ecliptic

    When first introduced to the concept of the ecliptic, I was under the impression that the ecliptic was the path taken by the Sun across the sky over the course of a day. That is to say, the rising in the east and setting in the west, due to the Earth's (daily) rotation from west to east. (Image...
  5. C

    What is the object's orbital path shown in the image?

    Summary: orbital path of an object Good morning I would like to ask the members of this forum their opinion regarding the object, which path I present in the image. The x-axis is the azimuth (towards me, the observer), and the y-axis the altitude. So it goes up in the trajectory shown (from A...
  6. Philosophaie

    A Calculating Compound Angle b/w Planet & Earth-Sun Vectors

    A certain planet has a vector (Recl, L, B). The Earth and Sun vector exists on ecliptic. I need to know how to calculate the compound angle between the planet vector and the Earth-Sun vector.
  7. H

    Why invariable plane is tilted to ecliptic plane?

    I googled and found this angle of Earth is claimed to be 1.5787 degree. Does it change over the time? Does anyone know any history of this tilt? I wonder if it's linked to global warming.
  8. havonasun

    I Gravitic Field of Rotating Disk-Shaped Mass Along Ecliptic

    I am curious to know if the gravitic field of a rotating, disk-shaped mass is denser along its ecliptic. I'm referring to rotating bodies such as stellar systems, galaxies, etc. I would like to know if a second mass, passing through the ecliptic, would experience a difference such as tidal...
  9. F

    I Orientation of the Earth, Sun and Solar System in the Milky Way

    I've been tinkering with a few diagrams in an attempt to illustrate the motion of the solar system in its journey around the Milky Way. I also wanted portray how the celestial, ecliptic and galactic coordinate systems are related to each other in a single picture. Note: in the Celestial, or...
  10. P

    I What shape is the ecliptic as seen from Earth?

    I want to build a model of how the ecliptic interacts with the horizon. The horizon appears to be a flat circle, so I thought I'd use a CD sized shape for that. What shape would I use for the ecliptic, and how large relative to the CD? I would like it to be as close as possible to the my...
  11. Jenab2

    I Position and Velocity in Heliocentric Ecliptic Coordinates

    There have been many questions on this forum about celestial mechanics in general, and concerning position and velocity in an orbit in particular. So I offer this post as a summary and reference. Here's a method for finding heliocentric position and sun-relative velocity in ecliptic coordinates...
  12. snoopies622

    Where Can I Find a Detailed Ecliptic Monitor for Tracking Solar Terms?

    I'm looking for a good source for the day by day (or even smaller graduations would be nice) angle of the sun along the ecliptic. I would like to know exactly when the various "solar terms" begin and end, and their dates and times vary from year to year...
  13. P

    Does the center of the galaxy intersect the ecliptic?

    Does the center of the galaxy intersect the ecliptic? If so, is it a temporary coincidence?
  14. E

    The Ecliptic and the Galactic Planes

    I heard recently that the ecliptic is about 60 degrees out of alignment with the galactic plane, and was tilted up in the "front". Is that true?
  15. J

    Exploring the Ecliptic Plane's Tilt

    Hi, 1/ The ecliptic plane is tilted at a constant angle (23,45°) as compared to the celestial equator. So, why the angle between ecliptic and equator is +23,45° at spring equinox and -23,45° at autumnal equinox ? 2/ On this document, ε = 23°27'. Why don't we have ψ = ε = 23°27' ? The...
  16. S

    Angle of crab pulsar to the ecliptic

    Hi there Can any1 tell me, what is the angle that the crab pulsar makes to the ecliptic? - (I am trying to make calculations that require knowledge of the radial velocity between the Earth and Crab) Thanks
  17. atomqwerty

    Ecliptic, Celestial equator and horizon?

    Hi, I think I have I little misunderstood about these three concepts: Ecliptic Celestial equator Horizon Can someone explain me the difference between them, specially between the second and the third ones? Thank you carlos
  18. Helios

    Can a Sundial Measure Ecliptic Longitude Accurately?

    I have an idea how to measure the ecliptic longitude with a sundial type device. Ecliptic longitude is a astronomical variable so I chose this forum. Suppose we have a verticle flag pole poised on the equator of the Earth. A "coordinate circle" is drawn that surrounds the flag pole, radius =...
  19. S

    Earth-Sun Vector, Ecliptic to Equatorial Coordinates

    I'm writing some code in Python for an astrophysics project, and I need some help. The JPL Horizons website gives the earth-sun vector in the default reference plane "ecliptic and mean equinox of reference epoch". I need to convert this vector (3 vectors, actually, reproduced below) into...
  20. W

    I can't understand why the sun moves across the ecliptic

    I can't understand why the sun moves across the ecliptic :( I've been searching for hours and I've found nothing more than "because of the Earth's revolution around the sun", so I'm assuming this is extremely obvious - but I can't understand it. I understand why the declination angle of the...
  21. W

    Star Catalogue Question - Stars near the Ecliptic

    I'd like to create a catalogue of stars that are within a one degree belt along the ecliptic. Since most databases use RA/Dec coordinates, this appears to be a daunting task. Any suggestions?
  22. Helios

    Ecliptic Longitude and Right Ascension of the Sun

    Here's a question. Where do the ecliptic longitude and the right ascension ( of the Sun )reach their maximum difference? What is the declination for these events? What calendar dates do you suppose this happens? I know the answer. I've never heard anyone make this observation except me. These...
  23. S

    From polar to heliocentric ecliptic coordinates

    I'm currently studying how to calculate planetary orbits and I'm stuck. I have calculated the polar coordinates of the planet, with the at the origin and the x-axis as the striped line in this picture: Now I have to transform the polar coordinates into heliocentric ecliptic coordinates...
  24. S

    From polar coordinates to heliocentric ecliptic coordinates

    So I've calculated the polar coordinates of a planet, with the sun at the origin and the x-axis being the striped line going from the sun towards point P. Now I have to convert these polar coordinates to heliocentric ecliptic coordinates. To do this, I have to convert to cartesian...
  25. K

    Would you expect comets to follow the ecliptic? Explain.

    Would you expect comets to follow the ecliptic? Explain.
  26. P

    The ecliptic planes of the Milky Way and the solar system

    Our Milky Way is a spiral galaxy whose ecliptic plane is the same with the ecliptic of the Sun (or nearly). So do you think all other solar systems in the Milky Way also have the same characteristics?
  27. P

    Question about the obliquity of the ecliptic

    Question about the "obliquity of the ecliptic" Hello guys, I hope I am in the correct forum for this question. If not, then I am sorry. How was it determined that the Earth was tilted roughly 23 degrees from its orbital plane? Or, how did the current locations/definitions of the north pole...
  28. M

    Position of ecliptic in northern hemisphere

    I live in the northern hemisphere about 38 degrees latitude. Last week I noticed that the plane of the ecliptic defined by venus Mars and Jupiter (or was it saturn?) was nearly over head at the zenith. I don't remember seeing this in my past looks at the sky. Is this a once a year thing like...
  29. G

    Ecliptic Plane's relation to Galactic Plane

    Hi, What is the orientation of the ecliptic plane of our solar system in relation to the plane of the galaxy? One source I found said they were aligned to within 5.5 degrees. http://www.Earth'sky.com/2000/es000304.html Another source I found stated that the orbital planes were 63...
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