Not all stars can be seen with the naked eye. Some celestial drawings consist of such dim bodies, that to admire them requires at least binoculars and ideal viewing conditions. A good example is the constellation Hydra, known to many residents of the southern part of our country. It is famous for its impressive size and difficult to distinguish luminaries in its composition.
Location
Hydra occupies a vast area in the sky, however, it belongs to the equatorial constellations, and therefore it can be fully observed only in the south of Russia. In order to find the constellation, you need to find its more visible neighbors. It is located south of the celestial drawings of the Virgin and Leo. The brightest point of Hydra, the star Alphard, is located near Regulus (the alpha of Leo). The most noticeable luminary of the August zodiac sign lies north of the alpha of the described heavenly pattern.
Hydra is best seen from February to March. It will turn out to be admired under conditions of clear weather and lack of artificial lighting. If it is not possible to identify the constellation Hydra, a photo from the Internet, including the location of all its elements, will help to recognize it.
Legendary monster
Despite its dullness, the constellation is one of the oldest. It is mentioned in the catalog of Ptolemy, compiled in the second century AD. There Hydra, however, is called the "Water Serpent." Probably, it is associated with one of the legends about the origin of the constellation. In it, the Greek god Apollo sent a raven for water. He fulfilled the assignment, but, together with the life-giving moisture, scooped up a serpent with a bowl. An angry god threw all the participants into the sky. So the constellations Water Snake, Raven and Bowl appeared.
More often, however, the heavenly drawing is associated with the Lernean Hydra, which Hercules defeated during his second feat. A huge monster with several heads and poisonous breathing was almost immortal. Not everyone could cope with it. In place of the severed head, two new ones immediately grew. The hero was able to defeat the monster with the help of cunning and ally of Iolaus. In memory of the feat, the gods placed Hydra in the sky.
Snake heart
The constellation Hydra has only one fairly bright star. This is Alphard, alpha of the heavenly figure. The name of the star translates as “lonely”, which once again emphasizes the absence of nearby visible objects. Also, the luminary bears several more no less sonorous names: the Heart of Hydra, the Heart of the Big Serpent, the Secluded snake. Its brightness is estimated at 1.98 magnitude.
Alphard is a triple system. Its main component is 40 times larger than the Sun in size and refers to variable luminaries. A small double star revolves around it. Alphard is approximately 177 light-years distant from the Sun.
In ancient Chinese chronicles, the alpha of Hydra was called the Red Bird. The reason for this is not difficult to find out - just find a star in the sky. It has a reddish tint.
Shock wave
However, not only Alphard adorns the constellation Hydra. The outline of this heavenly drawing includes several interesting objects. One of them is R Hydra, a variable star such as the Worlds of Whale. It separates from the Earth about 538 light-years. The star belongs to the red giants of the spectral class M.
The apparent brilliance of Hydra R varies from 3.21 to 11.00 magnitude. The period during which the luminary transforms so radically is approximately 390 days. The Hydra R is known in many respects due to the fact that in 2006 the Spitzer orbital telescope made an infrared photograph of it. The shock wave is clearly visible in the image , which is formed upon braking of interstellar matter as it approaches the star. The sealed border is located at a distance of 16.29 astronomical units from the object. The thickness of the shock wave, according to scientists, is 6.188 a. e. A star moves at a speed of 50 km / s. The shock wave ahead of it in mass is 400 times superior to our planet. A similar photo of such a phenomenon in the red giant was obtained for the first time.
Nebulae and Galaxies
What else can the Hydra constellation boast of? Photos of objects located on its territory demonstrate nebulae and galaxies. In 1785, William Herschel discovered a space formation here, later called the Ghost of Jupiter. This is the nebula NGC 3242. It can be observed in amateur telescopes. Before astronomers, she appears in a beautiful bluish-green guise.
The constellation Hydra also includes the galaxies NGC 3923 and NGC 3621. The latter is bright enough to be visible through an amateur telescope.
Such inconspicuous constellations of the winter sky, like Hydra, attract the attention of only the most curious lay astronomers. However, here, among the dim stars, there are many interesting objects for study. Alphard, galaxies and nebulae, young stars and brown dwarfs - the extended Hydra is rich in curious cosmic bodies and formations.