The 13th Sign of the Zodiac : Ophiuchus Serpent bearer.

The Astrological Lore of Ophiuchus: Ophiuchus was better known in classical times as Asclepius, [in Latin, Aesculapius] the God of Medicine. He learnt the art from Chiron, the Centaur. On either side of Ophiuchus in the heavens lie the two parts of the sign of the serpent he holds, Serpens Caput, the Serpent's Head and Serpens Cauda, the Serpent's Tail. The twined serpent staff is the badge of the medical profession to this day. [However, the sign of the serpent itself does not form part of the Real Solar Zodiac, though it does from part of the Planetary Zodiac.] It is from the Serpent that Ophiuchus learnt the secret of the Elixir of Life.
The even older Babylonian version is slightly different. Here the serpent is Tiamat, the Monster of the Bitter Ocean. Holding Tiamat is Marduk, the Sun God of the Babylonians. They are doing battle together in the eternal fight of good against evil.

Ophiuchus - the 13th Astrological sign of the Zodiac.

Ophiuchus (Ὀφιοῦχος IPA: /ˌɒfiːˈjuːkəs/) is a large constellation located around the celestial equator. Its name is Greek for 'snake-holder', and it is commonly represented as a man grasping the snake that is represented by the constellation Serpens. Ophiuchus was one of the 48 constellations listed by the 1st century astronomer Ptolemy, and it remains one of the 88 modern constellations. It was formerly referred to as Serpentarius (/ˌsɚpənˈtɛəriəs/), a Latin word meaning the same is its current name.
The most recent interpretation is that the figure of Ophiuchus represents the healer Asclepius, who learned the secrets of keeping death at bay after observing one serpent bringing another healing herbs. To prevent the entire human race from becoming immortal under Asclepius' care, Zeus killed him with a bolt of lightning, but later placed his image in the heavens to honor his good works. It has also been noted that the constellation Ophiuchus is in close proximity in the sky to that of Sagittarius, which has at times been believed to represent Chiron (the mentor of Asclepius and many other Greek demigods), though Chiron was originally associated with the constellation Centaurus.
Astrology
Although Ophiuchus intersects the ecliptic, it is not a zodiacal sign in most versions of astrology. The signs are defined as more-or-less 30-degree segments of the ecliptic, of which there are twelve, and they are named after nearby constellations at the time the system was developed, rather than being defined by the modern constellations. However, a few sidereal astrologers consider the sun to be in the sign Ophiuchus when it is in the constellation Ophiuchus, which as of 2008 is November 30 to December 17.
Although not incorporated into the 12-sign zodiac, Ophiuchus and some of the fixed stars that it is composed of were sometimes used by astrologers in antiquity as extra-zodiacal indicators (i.e. astrologically significant celestial phenomena lying outside of the 12-sign zodiac proper). An anonymous 4th century astrologer, often known as Anonymous of 379, seems to have associated "the bright star of Ophiuchus", likely α Ophiuchi, with doctors, healers or physicians.
Ophiuchus Wikipedia