Ophiuchus (Οφιούχος IPA: /ˌɒfiːˈuːkəs/) is one of the 88 constellations an was also one of the 48 listed by Ptolemy. Ophiuchus was formerly referred to as Serpentarius (/ˌsɚpənˈtɛəriəs/), the former originating in Greek and the latter in Latin, both meaning "serpent-holder". It is a large constellation located around the celestial equator between Aquila, Serpens and Hercules, northwest of the center of the Milky Way. The southern part lies between Scorpius to the west and Sagittarius to the east. Of the 13 zodiacal constellations (constellations that contain the Sun during the course of the year), Ophiuchus is the only one not counted as an astrological sign.