Dra · Draconis
Draco Constellation
IAU constellation mapDraDraco (Dra) is one of the 88 constellations recognised by the International Astronomical Union. It covers 1083 square degrees of the northern sky in quadrant NQ3. Its brightest star is Eltanin. The Latin genitive of the name is Draconis, used to form star names within the constellation. In Greek mythology, Draco is associated with greek tradition. The IAU standardised all constellation boundaries in 1930.
Quick facts
- IAU name
- Draco
- Abbreviation
- Dra
- Latin genitive
- Draconis
- Hemisphere
- northern
- Area
- 1,083 sq deg
- Brightest star
- Eltanin
- Quadrant
- NQ3
- Family
- Ursa Major
- Mythology origin
- Greek
- Discovery era
- Ptolemy's 48 (Almagest, c. 150 CE)
Mythology
Draco, the Dragon, winds around the north celestial pole in a vast sinuous curve. The constellation is associated with several different serpentine creatures in Greek mythology. In the most common identification it represents Ladon, the hundred-headed dragon that guarded the golden apples of the Hesperides in Hera's sacred garden at the western edge of the world — one of the apples-fetching was the Eleventh Labour of Heracles, in which he either killed Ladon or circumvented it with the help of the Titan Atlas. In another identification Draco is the dragon that Athena hurled into the sky when the giants attacked Olympus, sending it spinning so fast that it tangled around the pole. Thuban (Alpha Draconis), though only magnitude 3.65, was the north pole star around 2700 BCE during the Egyptian Old Kingdom period, when the pyramids at Giza were being built. The Cats Eye Nebula (NGC 6543) in Draco is one of the most structurally complex planetary nebulae known, with a series of concentric shells, jets, and knots that provide evidence of episodic mass-loss by the central star. Eltanin (Gamma Draconis) was pivotal in James Bradley's 1725 discovery of the aberration of light, which confirmed that the Earth orbits the Sun.
Sources: Aratus Phaenomena 44-61; Apollodorus Bibliotheca 2.5.11; Hyginus Astronomica 2.3.
Overview
Draco is one of the 88 constellations formally recognised by the International Astronomical Union (IAU). It occupies 1083 square degrees of sky in the northern hemisphere sky, best visible at latitudes between +90 and -60 degrees in June. The constellation belongs to the Ursa Major family of constellations. Its Latin genitive is Draconis, the form used when naming stars within the constellation — for example, the brightest star Eltanin may appear in catalogues as Alpha Draconis or similar. The IAU standardised the boundaries of all 88 constellations in 1930 under the direction of Eugène Delporte, using straight lines of right ascension and declination to eliminate the ambiguities of earlier variable-boundary systems.
Notable stars
The brightest star in Draco is Eltanin. Individual stars within Draco are conventionally named using Bayer designation — Greek letters followed by the Latin genitive of the constellation name (Draconis) — introduced by Johann Bayer in his 1603 star atlas Uranometria. Flamsteed numbers (numeric designators followed by Draco) were added by John Flamsteed in his 1712 catalogue. Variable stars, double stars, and deep-sky objects within the Draco boundary are catalogued by the IAU with the abbreviation Dra.
History and mythology
The figure of Draco appears in the classical astronomical tradition. Ptolemy included this constellation in the Almagest (c. 150 CE), the definitive ancient catalogue of 48 constellations, which formed the foundation for Islamic, medieval European, and Renaissance astronomy. The constellation's figure and mythology were transmitted through works such as Aratus's Phaenomena, Eratosthenes's Catasterismi, and Hyginus's Astronomica. See the Mythology section above for the full narrative.
Sources & further reading (2)
- official-iau — accessed 2026-05-06
- encyclopedia — accessed 2026-05-06
Frequently asked questions
What does the name Draco mean?
Draco is the Latin name used by the IAU to designate this constellation. The name comes from classical Latin and Greek astronomical tradition. In star catalogues, stars within Draco are designated using the genitive form of the name (e.g. Alpha Draco or similar Latin genitive forms) — a naming convention introduced by Johann Bayer in his 1603 atlas Uranometria and still in use today.
How large is Draco compared to other constellations?
Draco covers 1083 square degrees of sky. The full sphere of the sky contains 41,253 square degrees, so Draco occupies about 2.6% of the total sky. For comparison, the largest constellation is Hydra at 1303 square degrees; the smallest is Crux at 68 square degrees.
When and where is Draco visible?
Draco is primarily a northern hemisphere constellation, best seen from mid-northern latitudes. Southern hemisphere observers may see it low on the horizon depending on their latitude. The brightest star, Eltanin, serves as the main visual anchor for locating the constellation. As with all constellations, the best viewing conditions are a dark sky away from artificial light pollution, with the constellation high enough above the horizon to minimise atmospheric absorption.
