Sco · Scorpii
Scorpius Constellation
IAU constellation mapScoScorpius (Sco) is one of the 88 constellations recognised by the International Astronomical Union. It covers 497 square degrees of the equatorial sky in quadrant SQ3. Its brightest star is Antares. The Latin genitive of the name is Scorpii, used to form star names within the constellation. In Greek mythology, Scorpius is associated with greek tradition. The IAU standardised all constellation boundaries in 1930.
Quick facts
- IAU name
- Scorpius
- Abbreviation
- Sco
- Latin genitive
- Scorpii
- Hemisphere
- equatorial
- Area
- 497 sq deg
- Brightest star
- Antares
- Quadrant
- SQ3
- Family
- Zodiac
- Mythology origin
- Greek
- Discovery era
- Ptolemy's 48 (Almagest, c. 150 CE)
Mythology
Scorpius, the Scorpion, is one of the most visually striking constellations in the sky, with its curving tail and brilliant red heart-star Antares — whose name means 'rival of Mars' because of its similar ruddy colour. In Greek mythology the Scorpion was sent by Gaia or by Artemis to kill Orion the Hunter. The motivation varies by source: in one version Orion boasted that he would hunt every animal on Earth, threatening to deplete the world's fauna, and Gaia sent the Scorpion to stop him; in another, Artemis's twin brother Apollo tricked her into shooting Orion by disguising him, and the Scorpion finished the deed. Whatever the cause, Scorpius and Orion were placed on opposite sides of the sky so they would never meet — as Scorpius rises in the east, Orion sets in the west, and vice versa. Antares (Alpha Scorpii) is a red supergiant with a diameter roughly 700 times that of the Sun, approximately 550 light-years from Earth. It is one of the largest stars visible to the naked eye. Near the tail of the Scorpion lie two spectacular star clusters, Messier 6 (the Butterfly Cluster) and Messier 7, both easily visible to the naked eye.
Sources: Aratus Phaenomena 634-646; Hyginus Astronomica 2.26; Aratus Phaenomena 637-640.
Overview
Scorpius is one of the 88 constellations formally recognised by the International Astronomical Union (IAU). It occupies 497 square degrees of sky in the equatorial sky region, crossing both hemispheres, best visible at latitudes between +45 and -90 degrees in June. The constellation belongs to the Zodiac family of constellations. Its Latin genitive is Scorpii, the form used when naming stars within the constellation — for example, the brightest star Antares may appear in catalogues as Alpha Scorpii 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 Scorpius is Antares. Individual stars within Scorpius are conventionally named using Bayer designation — Greek letters followed by the Latin genitive of the constellation name (Scorpii) — introduced by Johann Bayer in his 1603 star atlas Uranometria. Flamsteed numbers (numeric designators followed by Scorpius) were added by John Flamsteed in his 1712 catalogue. Variable stars, double stars, and deep-sky objects within the Scorpius boundary are catalogued by the IAU with the abbreviation Sco.
History and mythology
The figure of Scorpius 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 Scorpius mean?
Scorpius 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 Scorpius are designated using the genitive form of the name (e.g. Alpha Scorpius 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 Scorpius compared to other constellations?
Scorpius covers 497 square degrees of sky. The full sphere of the sky contains 41,253 square degrees, so Scorpius occupies about 1.2% 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 Scorpius visible?
Scorpius straddles the celestial equator and is visible from both hemispheres, though part of it may be low on the horizon depending on the observer's latitude. The brightest star, Antares, 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.
