Perseus

Perseus's own article already covers Algol, the Demon Star, and the August meteor shower that bears the hero's name. A third notable object in the same constellation has a claim to being one of the oldest continuously recorded deep-sky objects of all: the Double Cluster.

NGC 869 and NGC 884, the Double Cluster, are a pair of open star clusters lying close together in the sky, visible to the naked eye under dark conditions as a hazy patch and easily separated into two distinct groupings through binoculars or a small telescope. The pairing was recorded as early as the second century BCE by the Greek astronomer Hipparchus, whose star catalogue is among the oldest systematic surveys of the sky to survive in any form, making the Double Cluster one of very few deep-sky objects, as opposed to individual bright stars, with a documented observational history stretching back that far.

Unlike Algol's eclipsing dimness or the Perseids' brief August visibility, the Double Cluster is simply there, a stable, unchanging pair of star groups that has looked essentially the same to observers for over two thousand years, a rare case of a faint object that predates most named individual stars in the historical record rather than being a modern telescopic discovery.

Perseus, already carrying a beheaded monster's eye and a meteor shower named for itself, holds this older, quieter object as well.

Perseus is a prominent northern constellation, one of Ptolemy's forty-eight, named for the Greek hero who slew the Gorgon Medusa and rescued the princess Andromeda from the sea-monster. It lies amid the figures of that myth, Andromeda, her parents Cepheus and Cassiopeia, and the monster Cetus, so that the whole story is written across this quarter of the sky. Its second-brightest star, Algol, the Demon Star, marks the head of Medusa and is a famous eclipsing variable whose regular dimming was noticed in antiquity and gave it its ominous reputation. The constellation also hosts the radiant of the Perseid meteor shower. These are the features of Perseus as the classical and modern astronomical traditions describe it, distinct from the zodiac; the constellation is a star pattern, not an astrological sign.

The giraffe constellation Camelopardalis, immediately north of Perseus, has no ancient pedigree at all; it was introduced only in the early seventeenth century, credited to the Dutch cartographer Petrus Plancius and popularised by Jakob Bartsch in 1624, filling a large, genuinely faint gap between Perseus, the two Bears and Cassiopeia that the Ptolemaic tradition had simply left blank.