'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 supporting 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.
Notable features
The brightest stars in Ophiuchus include
α Ophiuchi, called Rasalhague (at the figure's head), and
λ Ophiuchi, a triple star (at his elbow).
RS Ophiuchi is part of a strange 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.
[1]
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 straight up from ν in the chart.)
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.
[1]
Notable deep-sky objects
Ophiuchus contains several star clusters, such as
IC 4665,
NGC 6633,
M9,
M10,
M12,
M14,
M19,
M62, and
M107, as well as the nebula
IC 4603-4604. The unusual galaxy merger remnant
NGC 6240 is also in Ophiuchus.
Mythology
There exist a number of theories as to whom the figure represents.
The most recent interpretation is that the figure represents the healer
Asclepius, who learned the secrets of keeping death at bay after observing one serpent bringing another (which Asclepius himself had fatally wounded) healing herbs. To prevent the entire human race from becoming immortal under Asclepius's 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.
Another possibility is that the figure represents the
Trojan priest
Laocoön, who was killed by a pair of sea serpents sent by the gods after he warned the Trojans not to accept the
Trojan Horse. This event was also memorialized by the sculptors
Agesander,
Athenodoros, and
Polydorus in the famous marble sculpture ''
Laocoön and his Sons'', which stands in the
Vatican Museums.
A third possibility is
Apollo wrestling with the
Python to take control of the
oracle at
Delphi.
There is also the story of
Phorbas, a Thessalonikan who rescued the people of the island of
Rhodes from a plague of serpents and was granted a place in the sky in honor of this deed.
History

Johannes Kepler's drawing depicting the location of the ''stella nova'' in the foot of Ophiuchus.
This constellation, known from antiquity, is one of the 48 constellations described by
Ptolemy. It has also been known as '''Serpentarius''', a Latin form of its name.
The most important historical event in Ophiuchus was the
Supernova of 1604, whose explosion was first observed on
October 9,
1604, near θ Ophiuchi.
Johannes Kepler saw it first on
October 16 and studied it so extensively that the supernova was subsequently called Kepler's Supernova. He published his findings in a book titled ''De stella nova in pede Serpentarii'' (On the New Star in Ophiuchus's Foot).
Galileo used its brief appearance to counter the
Aristotelian dogma that the heavens are changeless.
It occurred only 32 years after another supernova in
Cassiopeia that had been observed by
Tycho Brahe; the last supernova before then had occurred in
1054 (see
Crab Nebula), and after Kepler's, no further naked-eye supernovae were observed until
1987 (see
Supernova 1987a.)
Astrology
In the
2nd century, Ptolemy listed 29 stars in Ophiuchus. He recognised that most of those stars were north of the
ecliptic (the path of the Sun through the sky); however, four of them (today known as 36 Oph, 42 θ Oph, 44 Oph, and 51 Oph) he recognized as being south of the ecliptic. Therefore, the Sun passed through the constellation of Ophiuchus as it was recognised by Ptolemy. However, Ophiuchus is not a zodiacal sign in
Western astrology due to a historical system in which 12 signs divided equally into 30 degrees each are vital. At present, the Sun is in Ophiuchus from
November 30 to
December 17.
References
1. Star 'soon to become supernova'
★ Ian Ridpath and Wil Tirion (2007). ''Collins Stars and Planets Guide'', HarperCollins, London. ISBN 978-0007251209.
External links
★
The Deep Photographic Guide to the Constellations: Ophiuchus
★
Ophiuchus the Zodiac Sign this is a pro-astrology link
★
'WIKISKY.ORG:' Ophiuchus constellation
★
Star Tales – Ophiuchus