Hydrus

When and where to look for Hydrus

Hydrus crosses the meridian — its highest point in the sky — at local midnight around October, which makes the months from September to November the easiest time to find it in the evening. It spans declinations -77.3° to -61.6°, so visible from everywhere south of about 13°N.

The quickest way to find it is to open the live AR sky map and point your phone at the sky — if Hydrus is above your horizon right now, its figure is drawn in the position it genuinely occupies above you.

Brightest stars in Hydrus

Magnitude runs backwards: lower numbers are brighter, and anything below about 6.5 is beyond the naked eye under a dark sky.

What Hydrus is made of

The catalogue lists 34 stars within Hydrus, of which 34 are magnitude 6.5 or brighter — the limit of what an unaided eye picks up under a genuinely dark sky. The rest need binoculars or a telescope.

Spectral make-up

Spectral class is a temperature ordering, running from O at around 30,000 K down to M below 3,500 K. A constellation is a direction, not a group, so this is simply what happens to lie along that line of sight.

The closest catalogued star in this direction is Bet Hyi at 24.3 light years. The most distant is HD 8810 at roughly 903 light years — stars that appear side by side here are nothing of the sort.