Ophiuchus actually exists in the Milky Way, but in astrological sense, it does not belong to the zodiac. At first, astrology imagined the universe as a sphere, and the trajectory of the sun on the sphere was called the ecliptic. The desert island is divided into twelve parts, and the famous twelve constellations are named and marked, which does not correspond to astronomy.
Extended data:
Ophiuchus is one of the zodiac signs. Seen from the earth, Ophiuchus is located to the south of Ursa major, to the north of Scorpio and Sagittarius, and to the west of the Milky Way. Ophiuchus is the only constellation connected with another constellation-Ophiuchus. At the same time, Ophiuchus is the only constellation that spans the celestial equator, the Milky Way and the ecliptic.
Ophiuchus is big and wide, rectangular, and the equator of the celestial sphere passes through this rectangle diagonally. Although Ophiuchus spans a short galaxy, the center of the Milky Way is Sagittarius, not far from Ophiuchus. The Milky Way has a prominent part here, forming the widest area of the Milky Way. You can see the latitude change between +80 and 80.