Serpens: the Serpent Constellation

Structure and notable features

The constellation is conventionally described in two parts: Serpens Caput (the head) and Serpens Cauda (the tail). Between them lies Ophiuchus, the Serpent Bearer, which gives the impression that a human figure holds the snake. Within both sections astronomers find a variety of stellar types and a number of star clusters and nebulae that are targets for amateur telescopes.

• Serpens Caput: the western portion, containing several of the constellation's brighter stars and open clusters.
• Serpens Cauda: the eastern portion, richer in faint nebulosity and additional star fields.
• Deep-sky objects: globular clusters, open clusters and emission nebulae are scattered through both parts.

Historically, Serpens and the adjacent Ophiuchus have roots in ancient Greek astronomy and mythology. The image of a man restraining a snake is associated with healing and medicine in several classical tales, and that symbolism survives in star charts and in the constellation names used today.

For observers, Serpens offers satisfying variety rather than a single outstanding star. Its split layout makes it distinctive on star maps, and it lies along the Milky Way in places, so binoculars and small telescopes reveal many faint stars and cloudy patches. Best viewing is during late spring and summer evenings in the northern latitudes when the constellation climbs higher in the sky.

Distinguishing facts: Serpens is one of the few constellations separated into two noncontiguous parts; its association with Ophiuchus creates a visually compelling scene and a useful example when introducing the sky’s mythological constellations to beginners.