Ophiuchus Constellation Facts

Ophiuchus wasn’t always a popular or talked about constellation, but it’s a treat for amateur astronomers to explore. It is rising in prominence due to its size, position, and notable objects– not to mention its fascinating history that has compelled more people to pay attention to it in recent times.

Ophiuchus, which is also sometimes called by its Latin name Serpentarius, was one of the first constellations recognized and documented by the 2nd Century Greek astronomer Ptolemy. Though its form is vague, Ophiuchus represents the mythological healer, Asclepius. It is a southern sky constellation that you can spot near the celestial equator.

Its location has caused some confusion. Because it crosses the Eliptic (and is positioned in between Scorpius and Sagittarius), it’s often incorrectly assumed that Ophiuchus forms part of the Zodiac. In reality, it’s included in a family of constellations known as the Hercules family: a group of constellations that share several important features such as how close they lie to the celestial sphere and a common history.

How to Locate Ophiuchus

Ophiuchus isn’t as obvious as some other constellations, but it won’t be difficult to find if you know what to look for. It’s the 11th biggest constellation of the 88. The southern end of Ophiuchus is wedged between Scorpius which is east of the constellation and Sagittarius to the west. Other bordering constellations are Libra, Aquila, Serpens, and Hercules.

This constellation is easily viewed in the southern hemisphere during winter. In June, it will be overhead at midnight and is visible through to October, when you can see it in the evenings.  You can pinpoint it by its brightest star, Ras Alhague.

Even though most of Ophiuchus’s area lies south of the equator, you can still see it from the Northern Hemisphere. Just look opposite Orion during the summer months. However, from the Arctic Circle it becomes more difficult to observe it because of the midnight sun obscuring it and its low position on the Horizon anyway. What’s interesting though, is that even from the Arctic Circle you may still be able to see it for a few hours in the afternoon, when the Sun lies below the horizon and daytime stars can be observed.

Ophiuchus Mythology and History

Ophiuchus is closely linked to the myth of Asclepius, who had healing hands and could revive the dead. He was the son of Apollo, who discovered how to heal by observing snakes.

In one story, Prince Glaucus died after drowning in a container of honey. A snake approached Glaucus’ body, and Asclepius killed it before it could make its move. A second snake then placed a healing herb on its dead body, and the snake was revived. Having witnessed this, Asclepius then placed the herb on Glaucus’s body, bringing him back to life.

Other variations say that Asclepius was taught how to heal by Chiron– a centaur. There is also a tale in which Athene gives Asclepius the healing blood of Medusa, subsequently giving him the power to resurrect.

Because he was so powerful, other gods saw him as a threat to the balance of the world. Hades grew concerned that Asclepius’s power would cause a shortage of dead souls for him to manage. He complained to his brother, Zeus, who then struck and killed Asclepius with a lightning bolt.

Zeus then projected Asclepius’s likeness into the sky as the constellation Ophiuchus, to honor his spirit and good contributions to the world.

There are also some suggestions that Ophiuchus stems from the Babylonian myth of the god Nirah, who was associated with snakes and believed to sometimes take on the appearance of a snake.

Ophiuchus Constellation Stars

Ophiuchus contains a variety of notable stars. Amateur observers can find binary stars, variable stars and even supernova in this constellation.

  • Alpha Ophiuchi/ Ras Alhague: The brightest star in the constellation is Alpha Ophiuchi or Ras Alhague. It is a binary star comprised of a white giant primary, and secondary main sequence dwarf star. The former has a mass times the sun, while the latter is equivalent to 85% of the sun’s mass. Ras Alhague lies just under 50 light-years from Earth and has an apparent magnitude of 2.07. This binary star marks Asclepius’s
  • Eta OphiuchiSabik: Despite its designation ‘Eta’, Sabik takes the number two spot for the brightest stars in Ophiuchus. It is located almost 90 light-years from the Sun and shines at magnitude of 2.43. It is also a binary star, but this time the pair consists of two white main sequence dwarves. The brighter star has a magnitude of 3.05 while the secondary has a magnitude of 3.27.
  • Zeta Ophiuchi: The third brightest star in the constellation is Zeta Ophiuchi, also known simply as Ophiuchi. The star is thought to be only about 3 million years old but is quite a large star. Zeta Ophiuchi is a blue main sequence star of magnitude 2.56. It lies just under 370 light-years away from the Solar System. Zeta Ophiuchi is also a variable star. The star is large enough that it may end in a supernova event and leave behind a neutron star.
  • Barnard’s Star: This red dwarf star is the fourth closest star to the Solar System, though at magnitude 9.54, it is too dim to see with the naked eye. This star the largest known proper motion relative to the Sun, and was named for the astronomer E. E. Barnard, who realized this in 1916. Barnard’s star is found 5.980 light-years away from Earth.
  • Delta Ophiuchi/ Yed Prior: This magnitude 2.75 star has a mass one and a half times that of the Sun, and is a possible variable star. It lies just over 170 light-years from the Sun and is the optical double of Yed Prosterior. These two stars form Asclepius’s left hand.
  • Epsilon Ophiuchi/ Yed Posterior: Approximately a billion years old, Yed Prosterior is 54 times more luminous than our sun. It is found over 106 light-years from our solar system and has a magnitude of 3.22. It’s a yellow giant star.
  • Nu Ophiuchi/ Sinistra: This is an orange giant some three times the mass of the Sun, and 123 times more luminous. It also has a solar radius 14 times that of the Sun. Sinistra has a magnitude of 3.33 and is located over 150 light-years from the Earths. It has two companion brown dwarf stars orbiting it. The first was discovered in 2004 and is about 22 times more massive than Jupiter. The second was discovered in 2010 and is almost 5 times the mass of Jupiter.
  • Beta Ophiuchi/ Celbalrai: This star’s magnitude ranges between 2.75 and 2.77. It lies almost 82 light-years from Earth. It is suspected that Celbalrai has a companion planet, but this is unconfirmed. The star is 63.4 times more luminous than the Sun and is the fifth brightest star in Ophiuchus. It’s an orange giant, and its name stems from Arabic and means “The Shepard Dog”.
  • Kappa Ophiuchi: Kappa Ophiuchi is another orange giant in the constellation and another star which may be a variable star. It is located only about 92 light-years from the Sun and has a magnitude of 3.20.
  • 70 Ophiuchi: 70 Ophiuchi is another binary system in Ophiuchus, and is found only about 16 to 17 light-years from our Sun. The primary star shines at magnitude is 4.03. Its companion star is on the verge of the naked eye threshold at magnitude 6.00. Both stars are orange dwarves. 70 Ophiuchi is a BY Draconis variable: a specific type of variable star characterized by its rotation, starspots, and chromospheric activity.
  • GJ 1214: This is an exceptionally dim red dwarf star with a magnitude of just under 15! It is also very small – its mass is only about 16% percent that of the Sun, with a solar radius of about 20% the Sun’s radius. It is found around 48 light-years from Earth. An exoplanet orbiting this star was discovered in 2009.
  • Wolf 1061: The star Wolf 1061 is quite close to our Solar System, lying only about 13 or so light-years away. Despite its relative proximity, the red dwarf shines dimly at a magnitude of 10.10 and can only be seen through larger telescopes.
  • Kepler’s Supernova: Also known as Supernova 1604, this isn’t actually a true star, but rather the remnants of a supernova event. This interesting stellar object was first noted by the German astronomer Johannes Kepler who observed it for a year. The event occurred roughly 20,000 light-years from Earth and peaked at magnitude -2.5. It was so bright that it was visible to the naked eye in the daylight for weeks.

Deep Sky Objects in the Constellation Ophiuchus

As with its stars, Ophiuchus is home to a range of deep sky objects from prominent nebula to beautiful clusters. It contains seven Messier Objects.

  • Planetary Nebula M2-9: Popular names for this nebula are Minkowski’s Butterfly, the Butterfly Nebula, and the Twin Jet Nebula. It lies approximately 2,100 light-years away from our Solar System and has a magnitude of 14.7. It has a distinct shape formed by twin lobes emitted from a central binary star. It was found by the German-American astronomer Rudolph Minkowski in 1947.
  • Barnard 68: This is a molecular cloud that is approximately 500 light-years away from the Sun. Its highly dense concentration of molecular gas absorbs light from stars positioned behind it.
  • Little Ghost Nebula: This is a planetary nebula with a magnitude of 12.9. It’s found 2,000 light-years away from Earth. The nebula itself spans approximately one light-year across and contains a central white dwarf star. It was discovered by William Herschel.
  • Dark Horse Nebula: Situated close to Scorpius and Sagittarius, this nebula is large and obscures some of the Milky Way Galaxy. If viewing conditions are perfect and there is no light pollution, you’ll be able to see this one with the naked eye. It’s one of the largest dark nebula that we can observe and is characterized by its likeness to the silhouette of a horse.
  • Snake Nebula: This dark nebula lies approximately 650 light-years from Earth, and is recognized by its S-shape. It is included in the Dark Horse nebula and is situated to the left of the Barnard 68 molecular cloud.
  • Rho Ophiuchi Cloud Complex: Here’s another dark nebula for you to observe. It’s 460 light-years away from us and is one of the closest nebula to our Sun. As many as 425 infrared objects have been detected in this nebula. They’re most likely young stars that have formed.
  • NGC 6240: This is an ultra-luminous infrared galaxy. It is the result of two smaller galaxies colliding. It is interesting to note that NGC 6240 has two nuclei, both of which are active and irregular.
  • NGC 6633: Discovered by Philippe Loys de Chéseaux between 1745 and 1746, this is an open cluster that is 1,040 light-years away from our Sun. The cluster is home to approximately 30 stars and is similar in size to the full moon. The cluster has a magnitude of 4.6 and is 660 million years old.
  • IC 4665: This is another nice open cluster in the constellation. It is thought to be less than 40 million years old and is 1,400 light-years away from the solar system. At magnitude 4.2, it is easily visible with binoculars or small telescopes. You can see it with your naked eye too in good conditions.
  • Messier 10 (M10, NGC 6254): This globular cluster has a magnitude of 6.4 and lies 14,300 light-years away from the Sun. The clusters core spans 35 light-years across and has a spatial diameter of 83 light-years. It is 16,000 light-years from the Galactic Center and orbits the Milky Way every 140 years. It was discovered in 1764 by Charles Messier.

Ophiuchus Meteor Showers

There are four meteor showers in Ophiuchus. The Ophiuchuds peaks every year around June 20th. You can also see the Northern May Ophiuchuds, the Southern May Ophiuchuds, and the Theta Ophiuchuds.