Auriga

Auriga's charioteer carries Capella, one of the brightest stars in the northern sky, but the constellation's real density of interest lies lower down, in a chain of star clusters strung along its Milky Way backdrop.

Messier catalogued three open clusters in Auriga, M36, M37 and M38, each a loose gathering of a few hundred young stars born from the same cloud of gas and still travelling together, visible in a small telescope as a scattering of points rather than the smooth glow of a globular cluster. M37 is the richest and most populous of the three, M36 the most compact, and M38 the loosest, so that a single sweep across the charioteer's body moves through three different stages of how an open cluster can look depending on its age and density.

None of the three carries any myth of its own; they entered the astronomical record only once telescopes existed to resolve them; Charles Messier catalogued this kind of object in the eighteenth century specifically to stop comet hunters, himself included, from repeatedly mistaking a fixed, fuzzy cluster for a moving comet.

Auriga's identity as a charioteer carrying goat and kids therefore sits over a stretch of sky whose real astronomical interest was invisible to the culture that named it, recognised only once instruments existed capable of resolving a smudge of light into hundreds of individual, ordinary stars.

Auriga is a bright northern constellation, one of Ptolemy's forty-eight, representing a charioteer. Its leading star is Capella, one of the brightest in the northern sky, whose name means the little she-goat; the charioteer is traditionally shown carrying a goat and her kids on his shoulder, and the nearby stars are called the Kids. The Greeks variously identified the figure with Erichthonius of Athens, said to have invented the four-horse chariot, or with a herdsman. Auriga rides high overhead in winter and lies along the Milky Way, rich in star clusters. In astronomical tradition it is a pattern of stars rather than an astrological sign of the zodiac. These are the features of Auriga as the classical and modern traditions describe it, distinct from any astrological reading of the region of sky it occupies.

Auriga sits close by two constellations that did not exist for Ptolemy at all: Lynx, introduced by Hevelius in 1687 and reportedly named for how sharp-eyed an observer would need to be to make out its faint stars, and Camelopardalis, the early seventeenth-century giraffe filling the large blank stretch toward the pole; both fill sky the ancient tradition simply passed over as too faint to bother naming.