Star Tales – Hydrus

A small southern counterpart of the great water-snake, Hydra, with which it is not to be confused. This is one of several examples of the repetition of constellation figures in the sky, as in the Great and Little Bear, the Great and Little Dog, the two lions, the horses Pegasus and Equuleus, the Northern and Southern Crown and the Northern and Southern Triangle.

Hydrus shown by Johann Bode in his Uranographia. “Nubecula Minor”, at centre, is the Small Magellanic Cloud. Part of the Large Magellanic Cloud, Nubecula Major, is visible in the bottom right corner.

Hydrus was one of the 12 constellations introduced at the end of the 16th century by the Dutch navigators Pieter Dirkszoon Keyser and Frederick de Houtman and it first appeared on Petrus Plancius’ globe of 1598. It represents the sea snakes that the Dutch explorers would have seen on their voyages. Hydrus is a male water snake, whereas the much larger Hydra is a female. To emphasize the difference in gender, Nicolas Louis de Lacaille termed it l’Hydre Mâle on his planisphere of the southern skies published in 1756.

Hydrus snakes between the two Magellanic Clouds. The constellation’s brightest stars are of third magnitude, but none are named.