Ophiuchus, Converting between bases, Capricorn, 2008 Horoscopes, Arias, Aol Horoscopes

Ophiuchus formerly referred to as Serpentarius, the former originating in Greek and the latter in Latin, both meaning "serpent-holder," is one of the 88 constellations and was also one of the 48 listed by Ptolemy. 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.

It is best visible in the northern summer and located opposite Orion in the sky. Ophiuchus is depicted as a man grasping a serpent; the interposition of his body divides the snake into two parts, Serpens Caput and Serpens Cauda, which are nonetheless counted as one constellation.

The brightest stars in Ophiuchus include α Ophiuchi, called Rasalhague, and λ Ophiuchi, a triple star (at his elbow).

RS Ophiuchi is part of a class called recurrent novae, whose brightness increase at irregular intervals by hundreds of times in a period of just a few days. It is thought to be at the brink of becoming a type-1a supernova.

Barnard's Star, one of the nearest stars to the Solar System (the only stars closer are the Alpha Centauri binary system and Proxima Centauri), lies in Ophiuchus. (It is located to the left of β and just north of the V-shaped group of stars in an area that was once occupied by the now-obsolete constellation of Taurus Poniatovii, Poniatowski's Bull.)

In April 2007, astronomers announced that the Swedish-built Odin satellite had made the first detection of clouds of molecular oxygen in space, following observations in the constellation Ophiuchus.