Hydrus Constellation: The Ultimate Guide

Hydrus is one of the 88 modern constellations; it is said that it has no associated history in ancient Western cultures because it was not visible in those regions.

In the case of Greek culture, when Ptolemy wrote the Almagest, it did not mention the constellation Hydrus nor did it appear on the celestial maps of the time.

Hydrus is one of the faintest constellations. Most of its stars cannot be seen with the naked eye, so it was necessary to wait for telescopes to be invented to see them with clarity.

Hydrus was one of twelve constellations named by cartographer and astronomer Petrus Plancius from observations made by navigators Pieter Dirkszoon Keyser and Frederick de Houtman in 1592.

First, the constellation appears publicly on a celestial globe 35 centimeters (14 inches), published in 1597 in Amsterdam by Plancius and Jodocus Hondius.

The French explorer and astronomer Nicolas Louis de Lacaille named the constellation "l'Hydre Mâle," meaning "female Hydra," in the 1756 version of his planisphere of the southern skies, this he did to differentiate it from the constellation Hydra.

In 1922 the International Astronomical Association added the Hydrus constellation to the 88 official night sky constellations. Since then, it has not undergone significant changes in its boundaries or name.

Currently, Hydrus covers a total area of 243 square degrees in the night sky. This makes it the 61st constellation among the 88 constellations in the night sky.

Hydrus resides in the first quadrant of the Southern Hemisphere (SQ1) between latitudes 8° N and 90° S, which means that we can only see the constellation in the night sky from the southern part hemisphere.

Hydrus is visible in South America, Africa, Australia, and Antarctica.

Hydrus is not visible in regions above 5°N such as the USA, Mexico, Canada, Europe, Russia, Greenland, or Japan.

The best month to visualize the constellation Hydrus is November. It's visible in late fall and early winter. In the southern hemisphere, it is visible throughout spring and summer.

The constellation Hydrus is small but has second-magnitude stars that you can use to locate in the night sky, mainly the star Beta Hydri (β Hyi), the brightest star near the south pole.

The easiest way to locate the constellation Hydrus is by finding its brightest star Beta Hydri (β Hyi), the brightest star near the south celestial pole.

Many use Beta Hydri (β Hyi) as a reference to find the south celestial pole because the star Polaris Australis (σ Octantis), the closest star to the south pole, has a magnitude of only 5.42.

The bordering constellations of Hydrus are Dorado, Eridanus, Horologium, Mensa, Octans, Phoenix (corner), Reticulum, and Tucana.

In addition, Hydrus belongs to the Johann Bayer family of constellations; these include Apus, Chamaeleon, Dorado, Grus, Indus, Musca, Pavo, Phoenix, Tucana, and Volans.

The constellation Hydrus officially contains 33 stars, of which 8 form the central figure of the constellation; these are Beta Hydri, Head of Hydrus, Gamma Hydri, Delta Hydri, Epsilon Hydri, Eta-2 Hydri, Nu Hydri, and Zeta Hydri.

It is the brightest star in the constellation Hydrus with an apparent magnitude of +2.80. It is the closest bright star to the south celestial pole, as the southern hemisphere polar star Polaris Australis (σ Octantis) is very faint.

Beta Hydri is a subgiant star of spectral type G2IV1 with a surface temperature of 5750 K, only 30 K cooler than the Sun. It is 3.7 times more luminous than this, its radius being almost twice the solar radius.

With an apparent magnitude of +2.90, Alpha Hydri is the second brightest star in the constellation Hydrus. It is located 71.3 light-years from the earth.

Alpha Hydri is a star of spectral type F0V with a surface temperature of 7140 K. 26 times more luminous than the Sun; its radius is 3.3 times greater than the solar radius, with a mass between 1.9 and 2.0 solar masses.

Hydrus is also home to several deep-sky objects. Deep-sky objects often mean stellar cumulus, nebulae (body of interstellar clouds), or galaxies.

In the case of Hydrus, because it is a small constellation that only has star clusters, some of the most notable are:

It is a vast and ancient galaxy about 345 million light-years from Earth. Pink with white resembling a rose is the most notable deep-sky object in the constellation Hydrus.

The age of the globular clusters in this galaxy varies according to their proximity to the core. It has relatively young globular clusters around 400 million years old and even older ones around a billion years old.

It is a massive globular cluster with a mass of about 140,000 times the mass of the Sun. It is an ancient cluster, with an estimated 13.1 billion years, almost as old as the universe itself.

Hydrus is a constellation located primarily in the southern hemisphere. Its name comes from the latín and means "little hydra." It is not to be confused with the constellation Hydra.

It was one of twelve constellations created by astronomer cartographers from observations by explorers Pieter Dirkszoon Keyser and Frederick de Houtman.

The Hydrus constellation is located between latitudes 8° N and 90° S. The best month to observe the constellation is in November.

The easiest way to locate the constellation Hydrus is by finding its brightest star Beta Hydri (β Hyi), the brightest star near the south celestial pole.

The brightest star in the constellation Hydrus is Beta Hydri (β Hyi), with an apparent magnitude of +2.80.

The most notable deep sky body in the constellation Hydrus is the White Rose Galaxy.

1. https://www.constellation-guide.com/constellation-list/hydrus-constellation/
2. http://www.seasky.org/constellations/constellation-hydrus.html
3. https://theplanets.org/constellations/hydrus-constellation-facts-features/
4. https://www.britannica.com/place/Hydrus