November (Usually visible from southern latitudes)
Notes
Hydrus was intended to represent an actual water snake rather than the mythical Hydra depicted in its own much larger constellation elsewhere in the sky. These two similarly-named constellations are distinguished by grammatical gender in Greek: Hydrus is masculine, while Hydra is feminine. The genitive forms for the two names follow the same pattern: Hydri is used for objects in Hydrus, while Hydrae applies to objects within the boundaries of Hydra.
The thin constellation shape of Hydrus defines a 'slice' of space southward of the main disc of the Milky Way.
Since antiquity, the large and rich equatorialconstellation of Hydra. In the sixteenth century, a second such creature was added to the sky, defining the Lesser Water Snake in this small region between the two Magellanic Clouds.