Draco

Draco's own article rightly centres Thuban, the former pole star of the pyramid age. Coiled further along the dragon's long body is an object considerably harder to explain than a star that simply lost its job to precession.

The Cat's Eye Nebula, catalogued as NGC 6543, is a planetary nebula, the glowing shell of gas cast off by a dying, Sun-like star in its final stages, and Hubble Space Telescope images of it revealed a structure far more intricate than the smooth, simple shells seen around most other planetary nebulae: concentric rings, jets, knots and bubble-like features layered over one another in a pattern astronomers have not fully accounted for with a single explanation. Leading theories involve a companion star, or a central star that ejected material unevenly over repeated episodes rather than in one smooth outflow, but no single model has settled the question of how the nebula came to look the way it does.

That a small, historically minor object buried partway along Draco's coils turned out, once imaged in enough detail, to be one of the most structurally puzzling planetary nebulae known is itself a small irony: the dragon's own myth, guarding the golden apples until Heracles came for them, has a tidier ending than the star it is still guarding.

Draco, the Dragon, is a large northern constellation, one of Ptolemy's forty-eight, winding a long sinuous course between the two Bears and coiling around the north celestial pole. Because of the slow wobble of the Earth's axis called precession, its star Thuban was the pole star some five thousand years ago, in the age of the Egyptian pyramids, before that role passed to Polaris. In Greek myth the dragon is often identified with Ladon, the serpent that guarded the golden apples of the Hesperides and was slain by Heracles, who kneels nearby. In astronomical tradition the constellation is a pattern of stars rather than a zodiac sign. These are the features of Draco as the classical and modern traditions describe it, distinct from any astrological reading; its former pole star is a reminder that the sky's fixed points shift over the ages.

Draco's long coils border Camelopardalis, the early seventeenth-century giraffe filling the faint gap toward the pole, one of several constellations introduced in this period specifically because the region around the celestial pole, circumpolar and permanently visible from northern latitudes, had been left only partly mapped by the classical tradition.