Nomenclature
- Latin: Draco
- Genitive: Draconis
- Abbreviation: Dra
- Greek: Δράκων Drakon
- Arabic: al-Tinnīn
The Greek and Latin titles of Δράκων Drakon and Draco, respectively, both mean dragon. However, "dragon" in the ancient sense more so referred to a serpentine figure rather than the medieval giant lizard with wings. This association was reflected in the Arabic title for the constellation of al-Tinnīn, 'the serpent'.
Description
Draco, the Dragon, can be seen in the sky snaking around and partially encircling the constellation of Ursa Minor. Its head stars are comprised of those of the Lozenge, from which it then increases in Right Ascension and coils around to continue arcing around the bowl of the Little Dipper. According to Aratus in his Phaenomena, the tail of Draco terminates in line with the head of Ursa Major.
The path of the precession of the North Celestial Pole carved through Draco and nearly intersected the star Thuban (α Dra). In fact, Thuban was approached at around 0.1°, closer than Polaris will ever reach. As such, Thuban was the polestar of the era centred around 2800BC, after which the pole drifted through the head of Camelopardalis to where it is today.
Mythology
Ladon
The most popular association for Draco is that of Ps-Eratosthenes and Hyginus, who both attributed the constellation to Λαδων Ladon, guardian of the golden apple tree of the Hesperides. At the wedding of Hera and Zeus, Gaia came bearing a branch with golden apples as a wedding gift which Hera became enthralled by, and so they were planted in her gardens at Mount Atlas. The Hesperides, daughters of Atlas, kept picking the apples, and so Hera placed the serpentine dragon Ladon to guard the tree.
Eurystheus ordered Hercules to bring back the golden apples of the Hesperides for his eleventh labour. After travelling to Mount Atlas, Hercules loosed his arrows at Ladon, the tips covered with the poison of the Lernean Hydra, slaying the beast. According to Apollonius Rhodius, the Argonauts happened upon the decaying body of Ladon the next day, the Hesperides covering their heads in lamentation. To commemorate its guardianship of the golden apples, Hera placed the dragon Ladon in the sky. Zeus then placed Hercules in the sky, kneeling on the head of Ladon to commemorate their struggle.
According to Ps-Apollodorus, Ladon was the son of Typhon and Echidna, had one hundred heads, and could talk in different voices. Hesiod, however, mentions his parentage as of Phorcys and Ceto. The dragon is nonetheless depicted as single-headed in the sky.
Athena in the Gigantomachy
Hyginus posited an alternative association for the constellation. During the Gigantomachy, a dragon was flung at the face of Athena, who in turn threw it at the sky and fixed it at the pole. This story possibly elucidates an early origin for the constellation, as fixing the dragon at the pole could be interpreted as the pole lying in Draco, which we know was the case in the third millenium BC due to the effects of axial precession.
A Disguise of Zeus
Nursed at Mount Dicte on Crete by the nymphs Κυνόσουρα Cynosura and Ἑλικη Helice on honey and the milk of the she-goat Αμαλθεια Amalthea (α Aur), Zeus was hidden from his father Cronus so that he would not be eaten by him. When Cronus came to Crete in search of his uneaten son, Zeus transformed Cynosura and Helice in bears and himself into a dragon, evading capture through trickery. After the Titanomachy, Zeus commemorated their struggle for survival by placing his nurses in the sky as the Celestial Bears and himself as the Dragon, grouped together in the northernmost skies.
Apollo and Python
Πυθων Python was a serpent sent by Gaia to guard the oracle of Delphi at Mount Parnassus. When the young Apollo attempted to enter the oracle the snake blocked him, but he in turn shot his arrows at it and slew it. Thus, the oracle then became known as Πυθω Pytho, 'rotting', relating to the rotting corpse of the snake. The snake was then fixed to the heavens by Apollo to commemorate their struggle.
Cadmus and the Ismenian Dragon
Ps-Apollodorus stated that Cadmus, the founder of Thebes in Boeotia, sent some men to retrieve water from the Spring of Ares guarded by the Ismenian Dragon. These men were killed by the serpent, who in retaliation was slain by Cadmus. Athena bade Cadmus to plant its teeth in ground from which sprung up the warriors the Sparti, who then began killing each other. Five of them survived, Echion, Udaeus, Chthonius, Hyperenor, and Pelor, who were said to be the ancestors of the Thebans. To atone for the bloodshed caused at Ares's spring, Cadmus served him for a year, which during his time was equivalent to eight of ours. The serpent was then fixed to the heavens to commemorate its guardianship and struggle.
Stars
| IAU Name | Designation | Apparent Magnitude |
|---|---|---|
| Thuban | α Dra | 3.68 |
| Rastaban | β Dra | 2.81 |
| Eltanin | γ Dra | 2.23 |
| Altais | δ Dra | 3.07 |
| Aldhibah | ζ Dra | 3.17 |
| Athebyne | η Dra | 2.74 |
| Edasich | ι Dra | 3.29 |
| Giausar | λ Dra | 3.85 |
| Alrakis | μ Dra | 5.66 |
| Grumium | ξ Dra | 3.75 |
| Alsafi | σ Dra | 4.68 |
| Dziban | ψ1 Dra | 4.55 |
| Tianyi | 7 Dra | 5.42 |
| Taiyi | 8 Dra | 5.26-5.34 |
| Fafnir | 42 Dra | 4.82 |
| Funi | HIP 61177 | 8.74 |
| Alruba | HIP 86782 | 5.76 |
Asterisms
Sources
- Ridpath, Ian. Star Tales. link.
- Lafitte, Roland. Catalogue of Star Names Created in the Greco-Arabian Sky. link.
- Grant, Mary. The Myths of Hyginus (1960). Accessed via link.
- Condos, Theony. Star Myths of the Greeks and Romans: A Sourcebook (1997), pp. 101-103. link.
- Hard, Robin. Eratosthenes and Hyginus, Constellation Myths with Aratus's 'Phaenomena' (2015), pp. 63-65, 295-296. link.
- Kidd, Douglas. Aratus: Phaenomena (1997), pp. 75, 77. link.
- Gain, D. B. The Aratus Ascribed to Germanicus Caesar (1976), pp. 54. link.
- IAU WGSN. IAU-Catalog of Star Names (CSN). link.
- Stellarium Contributors. Stellarium Astronomy Software. link.