Serpens

Serpens's own article already notes its unique division into Serpens Caput and Serpens Cauda, head and tail, separated by the figure of Ophiuchus who grasps the snake between them. That structural oddity is worth dwelling on for what it says about how the modern eighty-eight constellations were assembled at all, since Serpens remains, uniquely among them, one figure officially split into two non-touching pieces on the sky.

When the International Astronomical Union fixed permanent constellation boundaries in 1930, every other ancient figure, however oddly shaped, was drawn as one continuous region; Serpens alone was left with its identity divided by another constellation's boundary running straight through where the snake's body would otherwise be continuous, a decision that preserved the ancient image of the serpent-bearer grasping a single snake rather than forcing the boundary-makers to either merge Ophiuchus and Serpens into one figure or draw the snake as though its middle simply did not exist.

The Eagle Nebula, sitting within Serpens Cauda, gained its own fame independently of this oddity: the Hubble Space Telescope's 1995 image of its central dust columns, quickly nicknamed the Pillars of Creation, became one of the most reproduced astronomical photographs ever taken, showing towering structures of gas and dust within which new stars are still forming.

A snake divided by its own handler, and inside the divided half, one of the most famous images modern astronomy has ever produced.

Serpens is a northern constellation, one of Ptolemy's forty-eight, representing a great serpent, and it is unique in being split into two separate parts, Serpens Caput, the head, and Serpens Cauda, the tail, divided by the intervening figure of Ophiuchus, the Serpent-Bearer, who is shown grasping the snake. The serpent and its bearer are usually identified with Asclepius, the healer, whose staff entwined with a snake remains a symbol of medicine. Serpens contains the notable Eagle Nebula in its tail. In astronomical tradition the constellation is a star pattern rather than a zodiac sign, though Ophiuchus, which divides it, touches the ecliptic and is the figure invoked in the recurring talk of a thirteenth sign. These are the features of Serpens as the classical and modern traditions describe it, distinct from any astrological reading.

Serpens's western neighbour among the modern constellations is a textbook case of patron flattery in the sky: Scutum, Sobieski's Shield, was introduced by Johannes Hevelius in 1684 to honour his patron, the Polish king John III Sobieski, commemorating his victory at the Siege of Vienna, and it is the sole survivor among a number of similarly flattering seventeenth and eighteenth-century constellations, most of which, honouring various German princes and the King of France's dynasty, did not survive into the standardised modern list of eighty-eight.