The daring Ophiuchus
The constellation Ophiuchus is not one of the most recognizable in the sky, since its stars are not brighter than the second magnitude, but once found in the sky, just above the Scorpio, you can also imagine the figure of a person (the Serpentario) holding a Serpent in his hands: from the image of Stellarium we see in fact that on the right and on the left of the daredevil there are the two parts in which the constellation of the Snake has been divided, the Head and the Tail, that we will visit in a next article...
Since I've talked about this character, without getting lost in the meanders of mythology, I'll immediately show you how he was depicted in antiquity and modern times: for better or worse the figure of a man is easy to find among the component stars (and afterwards the usual H.A.Rey will come to help us) and it's even easier to see a long string of stars like a big snake.
The name, the story, the myth
The Serpentarium and the Serpent that wraps itself around it, were seen in ancient times as a single constellation. The "battle", as reported by Manilio (1st century AD), "will last forever as long as they fight in equal conditions and with similar powers". In Greek "Ophiuchus" means fatigue, but there is no hero by this name. His figure is commonly identified with that of the legendary healer Aesculapius, supposed ancestor of Hippocrates, born about 460 B.C., the great physician of Cos, to whom is attributed the symbol of medicine, the caduceus, the stick with two snakes entwined.
The story of Aesculapius, Asklepios in Greek origin, is as follows: his mother Coronides was courted by Apollo, who had her guarded by a white raven. Enamoured of a man named Ischis, she, although she was pregnant with Apollo, lay with him. The raven immediately reported the news to Apollo, but the god, who thanks to his divinatory skills was now aware of everything, became angry with the animal for not having gouged out Ischis' eyes and cursed him, turning him from white to black as the raven is now (according to another myth, the 'animal changed color as a result of another lack of him, see Crow).
Apollo then confided the infidelity to his sister Artemis, the huntress, who threw the arrows of her iron against Coronides. Only when her body was laid on the funeral pyre did Apollo feel remorse. Nothing could be done for Coronides, but Hermes intervened to remove his unborn child from his mother's womb. Aesculapius was thus saved and then entrusted to the care of the wise centaur Chiron, who taught him the art of medicine. His ability, the ability to heal all the sick. And when Perseus cut off Medusa's head, the blood that dripped from the right side of her neck was collected, and Athena gave it to Aesculapius, so that, thanks to the properties he had, he could use it to raise the dead. However, this threatened the kingdom of the Underworld. Hades (Pluto) complained to Zeus, who, worried about these resurrections similar to a divine act for a mortal, struck Aesculapius with one of his lightning bolts, just as he was trying to resurrect Orion. In revenge, Apollo killed the Cyclops, creators of Zeus' lightning strikes.
Later he carried his mortal son first among the gods and immediately among the stars, because being mortal and having met the disapproval of Zeus, he could not share Olympus with the other gods, so he made sure that he was thus contemplated as a god.
According to Igino (64 B.C. - 17 A.D.) the explanation of how he is represented in heaven is traced back to the episode when Aesculapius was forced to heal Glaucus. He was locked up in a secret place. He meditated on what to do by holding a stick, when a snake clutched at that stick. Aesculapius, frightened, killed him as he crawled away, striking him several times with that same stick. Afterwards, another snake entered Aesculapius' place of captivity, carrying a blade of grass in its mouth, which it placed on the head of the unfortunate beast, and immediately came to life and ran away together. After analyzing that single blade of grass, he recognized it and contemplating the prodigy, he used that grass to resurrect Glaucus. Therefore it is said that the Serpent was placed both under the protection of Aesculapius and in the firmament.
The second story, instead, believes that the Serpentario is associated with Enkidu, friend of the Mesopotamian hero Gilgamesh.
It is one of Ptolemy's original constellations. Inside it there is a small group of stars that once formed a constellation of their own, called Taurus of Poniatowsky dedicated to the king of Poland, and that now represent a set of stars more or less weak around 66 Oph, that is 66, 67, 68 and 70 Oph.
This is how the constellation was represented in the Uranometry
as the astronomer Hevelius saw it (as always already reversed and mirrored, therefore with illegible writing!).
and according to the ultramodern Stellarium
In all cases we see a muscular character (depicted from behind or from the front according to the fashions of the time) not at all worried about holding a dangerous snake like anaconda in his hands. In other depictions the snake wraps the body of the unlucky man with a spiral, while wisdom would advise to hold the snake by the head: considering that under his feet there is even a big scorpion, we can say that Ophiuchus is going through a bad quarter of an hour.
A handful of stars nearby
Actually, among the even weaker stars that do not appear on the map, there are 3 others, spectacularly close: in order of distance we have the so-called Barnard's Star just 6al from us and two stars from the Gliese catalogue, the 628 and the 526, respectively 14 and 18 light years away! Ultimately, in this constellation there are 5 stars below 20 light years, which is almost a record!
In the table I have reported these 5 near stars plus 4 others under 60al, indicating for each one the link to the photograph of how the Sun would appear, having the possibility to go in orbit around the single star and looking back: we know that this is a forbidden dream (for the great distances at stake, even if the stars are near on a cosmic scale), achievable as always with our trusty navigator Celestia. We know that the representation that this program gives us is so realistic that many times it really seems to me to jump from star to star, maybe to find my unlikely star friends that as I make you know!
Let's analyse together the results of these nine trips, getting to know these stars a little better.
- Barnard's Star is a faint bright dot of 9.57 precisely because, although it is so close to us, it has a diameter equal to one fifth of our Sun and a brightness equal to half a thousandth. Our star appears (finally!) of first magnitude, almost aligned with the three stars of Orion's Belt, along the ideal line that leads to Sirius: a truly fascinating sight! I add that it is the star having the biggest motion in absolute, so much that we can speak of it as a wandering star rather than a fixed star. As the years go by she will get closer and closer to the Sun (but she's not pointing at the Sun! Catastrophe, don't worry!) coming in almost 10,000 years less than 4 light years from us, thus becoming the nearest star. Hoping that Stellarium is not wrong, we can see that around the year 5500 it will enter the constellation Hercules, to abandon it around the year 21000 and thus enter the constellation Dragon.
- Gliese 628 is definitely weak (tenth ) and a quarter of our Sun. From over there, our star is located near Aldebaran, near the Hyades, while, not far away, Orion has an amazing belt this time formed by 4 stars, with the addition of Sirius. A really exciting spectacle: if tomorrow we could reach the nearby stars, well, it would certainly be my favourite destination.
- 70 Oph is a fourth size star a little smaller than the Sun: from there our star is between Sirius and Orion, a little more displaced than what we see from Barnard's Star.
- Remarkable is the panorama that can be enjoyed from 12 Oph, with the Sun distant from Orion (in which the usual Sirius is placed) and from Aldebaran.
- From Rasalhague the Sun is under the constellation Orion, with a weak Sirius near it.
- In all other cases, however, our Sun becomes a dimly lit star anomime.
Hunting for big stars
Continuing in the usual search for remarkable stars, that most of the times we discover unexpectedly, this time we meet half a dozen stars physically of important size: from the diagram realized as always by the undersigned, we realize that any 37 Oph is 4 times bigger than the usual Aldebaran. Don't worry: my friends Thirty-sevenophians don't mind, I know them well... You just need to shake their nine hands one by one to become friends again as always... It takes a good half an hour, but it's worth keeping a cosmic friendship!
Seriously speaking, it must be said that we are used to this kind of comparisons that by now don't surprise us so much, but if anything, this time it's a pleasure to find among the biggest stars also a spectral class G9, similar to the Sun: it's e Oph, which stands out with a diameter of 42 times our star. Not bad! The Thirteenth Zodiac constellation?!
In the introductory note I had mentioned that Orion could be considered the thirteenth constellation of the Zodiac: I would just like to add, given to the hand, some considerations. In the diagram realized by two images taken from Stellarium, we see that the Sun, during its annual journey along the celestial vault (following the ecliptic, that we see drawn in red) crosses the constellation of Ophiuchus from November 29th to December 18th, after having crossed a small stretch inside the Scorpio.
This is an academic discourse, purely theoretical: the constellations of the Zodiac have always been considered 12, even if the stretch traversed by the Sun within them is never a twelfth of 360°, that is, the theoretical 30th. I absolutely do not want to leave Science to enter into facts and disquisitions absolutely unscientific and artificially and deliberately linked to the Zodiac: I add that thanks to Stellarium we can see scientifically that, for example, in the constellation of Virgo the Sun travels 43° (the maximum), while vice versa (as we have seen in the related article), the Sun travels a little more than 6° of the celestial vault within Scorpio.
With this I close saying that counting Ophiuchus among the constellations of the Zodiac would not add anything to the astronomical world, rightly busy studying much more interesting and important problems and themes.
Galaxies and nebulae
Wandering among the stars of Ophiuchus you may encounter several DSO objects, not as striking as spiral galaxies can be for example: we find a number of objects from the Messier catalogue, including seven globular clusters, rich in stars, but if we want all similar. That's why I collected them in the one image.
The object that we see here, rich in colours in a wonderful picture of the HST, is quite different in scope: it is the so-called Pipe Nebula (the nebula of the Pipe). In this case the pipe is located at the bottom left and from its stove come out volutes of smoke upwards, while to the right there is a dark path (called Dark River) that stretches towards an area full of colored stars: the most yellow one is Antares.
It is in any case dark stellar dust that hides the light of the stars behind, while that reddish spot below Antares is an emission nebula.
A few names
Here we come to see what and how many stars have received a name, though in many cases perhaps it is not even used.
- Rasalhague (α Oph): from Arabic, the head of the serpentarium
- Cebalrai (β Oph): from Arabic, the shepherd's dog, even if there is neither a dog nor a shepherd here...
- Yed Prior (δ Oph): from Arabic, the hand and the preceding Latin
- Yed Posterior (ε Oph): from Arabic, the hand and the Latin that follows
- Han (ζ Oph): found in internet
- Sabik (η Oph) : with an uncertain meaning, which would sound like the one above
- Marfik (θ Oph): from the Arabic, the elbow of the serpentarium
- Left (ν Oph): found on the internet, it should refer to Ophiuchus' left hand. This name would justify the representation of Ophiuchus' shoulders, as in that of Hevelius and Uranometria.
When and where is it visible?
Always considering a convenient time for everyone (9 p.m., just after dinner), Ophiuchus is located low on the eastern horizon at the beginning of May, while we find it on the opposite side, low on the western horizon, towards the end of October. In this period of time, between May and October, the constellation reaches its peak, in the South, at more than 40° on the horizon, in the first days of August.