Constellation, Hyi
Hydrus: the Male Water Snake
Hydrus covers 243 square degrees of sky, the 61st largest of the 88. Its brightest star is star HIP 2021. It is best placed in the evening sky in December.
Hydrus at a glance
| Fact | Value |
|---|---|
| IAU abbreviation | Hyi |
| Meaning | the Male Water Snake |
| Pronounced | HIGH-drus |
| Genitive, used in star names | Hydri (for example a Bayer name such as α Hydri) |
| Area | 243 square degrees, number 61 of 88 by size |
| Stars to magnitude 6 in our catalogue | 20 |
| Brightest star | star HIP 2021, magnitude 2.8 |
| Best seen | Evenings in December, when it is highest at 9 pm |
| Declination range | -82° to -58° |
| Borders | Tucana, Mensa, Octans, Horologium, Reticulum, Eridanus, Dorado |
Where on Earth you can see Hydrus
Hydrus spans declinations -82° to -58°. Every part of it rises above the horizon at some moment for observers between latitudes 90°S and 8°N. Some of it can be seen from latitudes 90°S to 32°N. South of 32°S none of it ever sets. This is geometry only: it ignores haze, hills and buildings near the horizon.
From six cities
| City | Latitude | Visibility | Middle at its highest |
|---|---|---|---|
| Pune | 18.5°N | Only part of it rises | below the horizon |
| New York | 40.7°N | Never rises | below the horizon |
| London | 51.5°N | Never rises | below the horizon |
| Tromsø | 69.6°N | Never rises | below the horizon |
| Tokyo | 35.7°N | Never rises | below the horizon |
| Sydney | 33.9°S | Never sets | 52° |
Hydrus's named stars
None of the stars brighter than magnitude 6 in Hydrus has a name approved by the IAU Working Group on Star Names.
How these facts were found
The name, meaning and boundaries are the IAU's. Area, borders and the latitude ranges are computed from those boundaries; the brightest star and the star count come from a magnitude-6 star catalogue; star names are matched to the catalogue by Hipparcos number and checked by position. The month is when Hydrus's middle crosses the north-south line of the sky at 9 pm local solar time. See How we know.
Sources
- IAU: The Constellations. Names, meanings, pronunciations and boundaries
- IAU Working Group on Star Names. The official names of stars
- astronomy-engine. The MIT licensed library that does the calculations, run on the page's build machine and in the app
- HYG database v4.4 (astronexus). Distances, spectral types and luminosities, licence CC BY-SA 4.0