The red line on the globe is the ecliptic.

The ecliptic is the orbit of the Earth around the Sun. As the Earth rotates around the Sun, it makes exactly one revolution a year and returns to its original position, and the path that the Sun takes is called the "ecliptic".

And the orbit of the Moon around the Earth, the "white way" and the orbit of the planets around the Sun are very close to the ecliptic. It is a large circle assumed by the celestial sphere, i.e. the projection of the Earth's orbit on the celestial sphere. The ecliptic and equatorial planes intersect at the vernal and autumnal equinoxes.

Because the Earth's axis of rotation is not perpendicular to the plane of revolution, the celestial equatorial plane does not coincide with the plane of the ecliptic, and the two planes have an angular angle of 23°26'21. (Measured in 2000 AD), the intersection of the two planes of the angle of the point will be even firm equinox ride the fall equinox.

Earth looking over, the sun towards the south becomes north, it is called the vernal equinox. From that fielding towards the east counts a circle, 0 ° to 360 °, is the ecliptic meridian, written as λ, the angle is called the ecliptic several degrees. The ecliptic latitude line is the north and south plus or minus 90° each.

From the center of the Earth, the ecliptic is very close to the Sun's apparent annual path in the stars. The difference between the ecliptic and the Sun's apparent annual path can only be detected by applying sophisticated astronomical instruments. The ecliptic is the base circle of the ecliptic coordinate system on the celestial sphere.

Extended information:

I. Relationship between the ecliptic and the equator

Because the Earth's axis of rotation is not perpendicular to the plane of the orbit, the plane of the equator is not parallel to the ecliptic. parallel to the ecliptic, but has an angle of 23°26', which is known as the angle of intersection of the ecliptic and the equator.

The equatorial plane and the ecliptic plane and the Earth's intersection of the great circle formed by the equator and the ecliptic, respectively, the intersection of these two planes exactly in a line of the Earth's diameter of the two endpoints is the famous bisector (equinoxes and autumnal equinoxes).

The bisector where the sun passes from south to north is called the vernal equinox or the first point of Aries, and the longitude of the ecliptic, which is usually labeled with the letter λ, starts at this point and goes eastward from 0° to 360°.

The latitude of the ecliptic, usually labeled with the letter β, is measured on the ecliptic as a base plane from 0° to 90° northward and from 0° to -90° southward. The vernal equinox is likewise defined as the origin of the equatorial coordinates, and the equinox longitude is also measured eastward from 0 to 24 o'clock, and is usually denoted by the letter α or R.A.

Equatorial latitude is denoted by the letter δ or Del. and is measured from 0° to 90° northward and from 0° to -90° southward from the equatorial plane. A simple rotation type allows α, δ and to λ,β to be converted to each other.

Two astronomical phenomena

1, the ecliptic

About the 5th century BC, the ancient Babylonian astronomers first used the concept of the "ecliptic". Imagine the whole sky as a big ball, and the stars are distributed on the shell, which is called the celestial sphere.

The ecliptic is the path of the sun across the celestial sphere. The area 8 degrees on each side of the ecliptic is the zodiac. The planets all orbit in the ecliptic. The Babylonians also divided the zodiac into twelve regions, however the names of these regions came from the ancient Greeks. In fact, most of the names of the constellations come from Greek mythology.

2. Ecliptic plane

The ecliptic plane is the plane in which the Earth's orbit lies. Because the gravitational pull of celestial bodies such as the Moon and other planets affects the Earth's rotational motion, the ecliptic's position in space is always changing in an irregular succession.

But in the midst of the variations, this plane always passes through the center of the Sun at any given time. The great circle where the ecliptic plane intersects the celestial sphere is called the ecliptic.

Reference:

Baidu Encyclopedia - Globe

Baidu Encyclopedia - Ecliptic