Abbreviation: Hyi

Genitive: Hydri

English: The Lesser Water Snake

Size Ranking: 61st

Area: 243 square degrees

Fully Visible: 8°N-90°S

The constellation chosen this month, Hydrus, is, yet again, another of the numerous lesser southern star patterns.

Hydrus is a fainter constellation invented in the 16th century by the Dutch navigators, Pieter Dirkszoon Keyser and Frederick deHoutman, and is situated between Achernar, αEri, and the south celestial pole. A further guide is to locate the two Magellanic clouds and Hydrus resides in the intervening area.

This constellation depicts a small water snake and should not be confused with the large water snake, Hydra, known since the time of the ancient Greeks.

Features of Interest:

One reference consulted described this constellation thus- ’A constellation in the far south – remarkably lacking in interesting objects.’! However, this is nearly correct, but not quite.

αHyi, is magnitude 2.9 white main-sequence star and is 71ly distant.

βHyi, at magnitude 2.8, is the constellation’s brightest star. It is a yellow star and is 24ly away.

γHyi,  is a red giant star of magnitude 3.2 and 214ly out in space.

π¹,π²Hyi, is a binocular pair of unrelated red and orange giants. π¹ lies 740ly away and is of magnitude 5.6, while π² is magnitude 5.7 and lies 468ly distant.


1. Redshift 2 – Maris Multimedia

2. The Guinness Book of Astronomy – Patrick Moore

3. Stars and Planets – Ian Ridpath and Wil Tirion

4. Sky Charts – Cartes du Ciel V 2.75.

5. NASA Picture of the day:

Large Magellanic Cloud NGC6934

Large Magellanic Cloud NGC6934





Small Magellanic Cloud NGC346

Small Magellanic Cloud NGC346