What is the so-called (ecliptic) of the ancients?

Simply put, the earth revolves around the sun once a year. From the earth, we see the sun moving 365 or 366 times a year in the sky. The route of the sun's movement is called the ecliptic-it is an imaginary great circle on the celestial sphere, which is the projection of the earth's orbit on the celestial sphere.

Definition of scientific terms of the ecliptic Chinese name: ecliptic English name: eclipti

Definition: 1: a great circle intersecting the celestial sphere on a plane parallel to the average orbital plane of the earth's revolution. Discipline: atmospheric science (first-class discipline); Dynamic meteorology (two disciplines)

Definition 2: A great circle intersecting the celestial sphere through the plane of the center of the celestial sphere and the average orbital plane of the earth's revolution. Discipline: astronomy (first-class discipline); Astrometry (two disciplines) This content is approved and published by the National Committee for the Examination and Approval of Scientific and Technical Terminology. The business card of the encyclopedia is the ecliptic, the great circle where the earth's orbital plane around the sun intersects with the celestial sphere. Because the earth's revolution is attracted by other planets, the moon and other celestial bodies, the position of the ecliptic plane in space changes irregularly. But in the process of change, the instantaneous orbital plane always passes through the center of the sun. This change can be expressed by a slow long-term movement plus some short-term changes.

Astronomy calls the annual apparent trajectory of the sun on the celestial sphere, that is, the great circle of the apparent path of the sun in the sky "ecliptic", that is, the projection of the earth's orbital plane on the celestial sphere.