The Sun’s path
The ecliptic and why the zodiac follows it
Follow Earth around the Sun to find the ecliptic, the Sun’s yearly path among the stars, and see how longitude along it places the Moon and planets.
01 · The reference
Start with Earth’s orbit around the Sun.
Earth goes around the Sun once a year in a flat plane. Extend that plane far enough and it meets the distant stars along a circle. From Earth, the Sun is always seen somewhere on that circle, in front of whichever stars lie beyond it.
As Earth moves, the line from Earth through the Sun sweeps around the stars, about 1° a day and once around in a year. That circle, the Sun’s yearly path against the stars, is the ecliptic.
02 · Close company
The Moon and planets stay close to it.
The Moon’s orbit and the planets’ orbits lie almost in the same plane as Earth’s. Seen from Earth, they all keep near the ecliptic. The celestial equator, set by Earth’s spin, is a different circle tilted well away from it.
Because the Sun, Moon and planets all travel close to one circle, a single angle along that circle locates any of them well. The two points where the Moon’s path crosses the ecliptic are its nodes, Rahu and Ketu.
03 · Measuring along it
A position is an angle around the circle.
Now picture the ecliptic as a circle around Earth. Longitude is the angle around it from a chosen 0°, counted in the direction the Sun moves. The full circle is 360°; the twelve signs are 30° each and the 27 nakshatras 13°20′ each.
Moving 30° changes the sign and moving 13°20′ changes the nakshatra. A tithi uses the same measure: it counts the Moon’s lead over the Sun in 12° steps.
Automatic playback is off because reduced motion is enabled. Use Play or the timeline to explore at your own pace.
What the ecliptic is
Earth travels around the Sun once a year, and its orbit lies in a plane. The ecliptic is that plane, and also the circle where it meets the sky. Seen from Earth, the Sun always lies on this circle.
As Earth moves along its orbit, the Sun appears in front of different stars. Its place shifts eastward by just under 1° a day, because 360° is covered in about 365¼ days. After one year it returns to the same stars. The ecliptic is therefore also described as the Sun’s yearly path against the stars.
The Sun’s brightness hides those stars during the day, so the path is not seen directly. It shows indirectly: the stars overhead at midnight lie roughly opposite the Sun, and they change through the seasons.
Not the Sun’s daily path
The Sun also crosses the sky from east to west every day. That daily motion comes from Earth turning on its axis, and it carries the stars along with the Sun. The slow eastward drift against the stars is a separate, yearly motion. Only the yearly motion traces the ecliptic.
Why positions are measured along it
The Sun lies on the ecliptic by definition. The Moon and the planets stay close to it, because their orbits lie almost in the same plane as Earth’s. Each orbit is tilted to Earth’s by a few degrees:
| Body | Orbital tilt to the ecliptic |
|---|---|
| Moon | 5.1° |
| Mercury | 7.0° |
| Venus | 3.4° |
| Mars | 1.8° |
| Jupiter | 1.3° |
| Saturn | 2.5° |
The tilts are measured from each body’s own centre of motion: the Moon’s from Earth, the planets’ from the Sun. Seen from Earth, a planet’s distance north or south of the ecliptic varies with the geometry, but it stays small compared with the whole circle.
Because every body is found close to one circle, a single angle along that circle is enough to say where each one is. That shared measuring line is what lets a chart compare the Sun, Moon and planets directly.
The name comes from eclipses. A solar or lunar eclipse can happen only when the Moon is at or very near the ecliptic, at one of the two crossing points explained in Rahu and Ketu.
Longitude and latitude
A position on the sky needs two angles. Ecliptic longitude runs around the circle from 0° to 360°, increasing eastward, in the direction the Sun moves. Ecliptic latitude measures how far north or south of the circle a body lies.
Chart positions use longitude. A Kundli divides the circle into twelve 30° signs, so 40° of longitude is 10° Taurus. The degrees guide explains the notation in detail. Panchang elements use the same measure:
- Nakshatra: the Moon’s longitude, in 27 divisions of 13°20′ each. See what a nakshatra is.
- Tithi: the Moon’s longitude minus the Sun’s, counted in 12° steps. See what a tithi is.
- Sankranti: the moment the Sun’s longitude crosses into a new sign.
Latitude is still real. It decides, for example, whether the Moon passes in front of a star or a little above it. It does not change which sign or nakshatra a body is in.
Why not the celestial equator?
Earth’s equator, projected onto the sky, forms another circle: the celestial equator. It is set by the direction of Earth’s spin axis, which is tilted about 23.4° to the orbit. The two circles therefore cross at two points and separate by up to 23.4° between them.
The celestial equator suits questions about Earth’s rotation, such as how high an object climbs or when it rises. The ecliptic suits questions about the Sun, Moon and planets, because those bodies travel along it. Zodiac positions belong to the second kind.
Where 0° begins
The circle has no built-in starting point, so a zodiac has to choose one. The tropical zodiac starts at the March equinox, one of the two places where the ecliptic crosses the celestial equator. A sidereal zodiac fixes its start against the stars instead, using an ayanamsa. The two starting points slowly drift apart, so the same position can carry a different sign in each.
panchang.now uses sidereal positions. The sidereal and tropical comparison and the ayanamsa guide explain the choice.
See the Sun’s and Moon’s longitudes in the Positions table on the Kundli page, or explore another topic in Learn.