Arcturus

ark-TOOR-uhs

greek: Ἀρκτοῦρος (Arktouros) · arabic: Al-Simāk al-Rāmiḥ

Definition

Arcturus (Alpha Boötis) is the brightest star in the constellation Boötes and the fourth-brightest in the whole night sky (apparent magnitude –0.05). A K1.5 III orange giant about 36.7 light-years from Earth, it currently projects onto the ecliptic — the Sun's yearly path — at roughly 24° tropical Libra. It is the 10th of the 15 Behenian Fixed Stars listed in the medieval Latin Hermetic tradition (BM Bodleian MS. 52), and one of the first-magnitude reference stars of classical astronomy.

In Tradition

In the joined Hellenistic, Latin, Arabic, and medieval magical fixed-star tradition, Arcturus is read as a major beneficial star. Robson (1923) gives it a Jupiter-Mars nature and ties it to riches, honors, and self-determination. The Arabic-mediated medieval Hermetic tradition assigns it talismanic correspondences — jasper and plantain — for fevers and for stopping bleeding. Brady's modern revival treats Arcturus as the pathfinder star of self-directed enterprise.

In Practice

Astrologers read Arcturus two ways: by its conjunction position in the zodiac (currently near 24° Libra, drifting at the precession rate of about 50″ a year) and by paran — the latitude-dependent way a star and a planet reach an angle of the chart at the same moment (see Brady). A conjunction of Arcturus with a natal planet, the Ascendant, or the Midheaven is treated as significant, and the star is read as amplifying whatever planet it touches. In the Behenian-Arabian magical tradition the talisman is made when Arcturus is rising and the Moon is conjunct it, using green jasper engraved with the star's character, worn for the medical uses named above.

Historical Origin

Arcturus is named in Hesiod's *Works and Days* (8th c. BCE) as a heliacal-rising marker for late winter. Ptolemy lists it in the *Almagest* star catalog (2nd c. CE). Robson's *The Fixed Stars and Constellations in Astrology* (1923, public domain) gives the standard pre-modern English fixed-star treatment. The medieval Hermetic 15-Behenian-stars tradition survives in BM Bodleian MS. 52, translated by John Michael Greer (2017) via Joan Evans's *Magical Jewels* (Dover 1976).

Definition

In Tradition

In Practice

Historical Origin

Further Reading