Thuban

Definition

Thuban (α Draconis) is a giant star of apparent magnitude 3.65 in the constellation Draco, lying in the coil of the Dragon between Ursa Major and Ursa Minor. Most famous as the pole star of the third millennium BCE — it was nearest the celestial north pole approximately around 2787 BCE, the era of the Egyptian Old Kingdom and the early Mesopotamian dynasties. Today, owing to the precession of the equinoxes, the celestial pole has migrated approximately 26° away from Thuban toward Polaris.

In Tradition

In modern Western fixed-star practice, Thuban is read as a star of ancient royalty, vigilance, and the guardianship of hidden things — connotations tied to its archaeoastronomical role as the Old Kingdom and Early Dynastic pole. Brady's *Book of Fixed Stars* gives the standard contemporary delineation. The Egyptian astronomical-iconographic tradition documented by Belmonte and Lull (2023) includes Thuban within the *Ikhemu sekiu* circumpolar grouping — "those who do not know destruction" — and identifies it as the architectural-orientation target of the third-millennium-BCE pyramid corridors.

In Practice

Astrologers locate Thuban in the modern era by ephemeris (it lies in the far northern sky in Draco, between the bowl of Ursa Major and the bowl of Ursa Minor). In fixed-star natal work the star is delineated when in tight orb (typically 1°) to a chart point or planet. Belmonte (2001) used the Phecda-Megrez (γ-δ Ursae Majoris) pair within the Plough asterism — which in the first half of the third millennium BCE pointed approximately toward Thuban — as the architectural-orientation target for the 4th-Dynasty Giza pyramids, with maximum precision around 2562 BCE. Modern fixed-star treatments tie the star to ancient royalty, the guardianship of hidden treasure, and the imperishability theme inherited from its Egyptian-circumpolar context.

Historical Origin

Thuban's role as the third-millennium-BCE pole star is documented archaeoastronomically through alignments of Old Kingdom Egyptian pyramid corridors (Khufu's Great Pyramid c. 2562 BCE) toward its then-position. The star is included in Ptolemy's *Almagest* (c. 150 CE) within the Draco catalogue. Belmonte-Lull (*Astronomy of Ancient Egypt*, 2023) anchor the Thuban pole-star era within Old Kingdom funerary cosmology.

Etymology

Origin: Arabic. Meaning: The snake / dragon.

Further Reading

• Bernadette Brady, Brady's Book of Fixed Stars
• Juan Antonio Belmonte & José Lull, Astronomy of Ancient Egypt
• Vivian E. Robson, The Fixed Stars and Constellations in Astrology