Hydra (Vasuki)
Hydra, resembles the shape of a water snake when stars in this constellation are imaginarily connected, as per Indian mythology!
Where should I see…Monoceros, is the constellation which is towards west of Hydra constellation. If
you move your eyes towards east, you will see another constellation named Libra. In the North of Hydra, you will find Virgo, Corvus, Crater, Cancer and Sextans and in South, Antlia, Pyxis, Puppis and Centaurus constellations respectively. Hydra is halfway above celestial equator and halfway below celestial equator, but its brightest star is below Celestial equator and so is fully part of Southern Hemisphere.
It covers up 1303 square degree area of the sky. Area wise it is the largest constellation in the entire sky.
When and What can I see…We can gaze at this water snake shape of Hydra constellation from January to June,
as seen from India.
All you need is your naked eyes other than clear skies to see 244 stars of this constellations, as they are the one which are brighter than the lower limit of our naked eyes (i.e. 6.5 apparent magnitude) to see faintest stars. The brightest star of this constellation is Alphard. The Hindu name of this star is Ekaki.
Constellations are made up of single, binary (apparent and absolute), multiple and variable stars. Out of total 244 stars of different types, here is the list of 20 brightest stars as per their nature:
| Binary / Multiple Star system | Variable Stars | Binary and Variable Stars | Single stars |
| 5 | Ukdah | Alphard | Zhang |
| – | 1 | Ashlesha | Minchir |
| – | – | 3 | 6 |
| 5 | 2 | 5 | 8 |
Mythology stories…
As per Hindu mythology, there are no such known stories for this constellation.
Deep Sky Objects…
ESO-510-G13 || Spiral Galaxy
Hydra Cluster or Abel 1060 || Galaxy Cluster
Jupiter’s Ghost or NGC 3242 || Planetary Nebula
All the stars that we see naked eyes, all belong to our own, Milky Way galaxy (Akash Ganga Tara Vishv). Bright stars can be seen naked eye and faint one through telescope. But the curtain of sky that we see in 2D is actually a huge universe we are talking about, with 3 dimension. There are many nebulous objects visible in every constellations. They differ widely by distances and nature. Like Emission Nebula, Reflecting Nebula, Absorption Nebula, Star Birth Nebula, Supernova Remnants (SNR) and Open Stars cluster which are within the disk of our own Milky Way galaxy. Globular cluster are also found, which are in the halo of our galaxy and some most distant objects like galaxies are also visible through telescope. Such objects are defined as “Deep Sky Objects”.
In this constellation there are 350 such different types of Deep Sky Objects observed. Below is the list of 20 brightest Deep Sky Objects:
M48 or NGC 2548 || Open Cluster
M68 or NGC 4590 || Globular Cluster
NGC 4980 || Spiral Galaxy
| Galaxy | Open Cluster | Globular Cluster | Nebula | Supernova Remnant | ||
| Naked eye visibility | – | M 48 | – | – | – | |
| Visible through Telescope | M 83 | – | M 68 | 1 | – | |
| 15 | – | 1 | – | – | ||
| 16 | 1 | 2 | 1 | – |
NGC 3054 || Spiral Galaxy
NGC 3109 || Barred Spiral Galaxy
NGC 3314 || Pair of Overlapping Spiral Galaxies