Clasificación de dos puntos
See also: Hydre
The male Hydre (not to be confused with immense the Hydre, known as “Hydre female”) is small a Constellation located close to the celestial south pole and cuts out part of space located under the plan of the Milky Way. It thus does not contain enormously visible star S.
History
The constellation of male Hydre is a modern creation. She was invented by the navigator S Dutch Pieter Dirkszoon Keyser and Frederick de Houtman at the end it 16th century to fill a space without denomination close to the celestial south pole. She was popularized by Johann Bayer during the publication of sound Uranometria in 1603. Sometimes called “Alarming specter”, it has nothing to do with the Hydre de Lerne of the Greek Mythologie.
The Astronome Julius Schiller combined male Hydre and the Toucan to form the biblical constellation of the Archange Raphaël. Like the other religious constellations of Schiller, it was not long in falling in disuse.
Observation of stars
; Localization of the constellation The male hydre belongs to the small group of constellations located around Achernar, the terminus of the river Éridan. It is located at the immediate South of this star.; Form constellation The constellation with the general form of a fresh water hydre which would have been fixed on Achernar.
The star nearest to Achernar, with ~5° with the SE, is α Hyi, which marks the foot of the hydre.
In this direction, still ~5° further, one finds a small arc of circle formed by ε (in the East), δ (in the center) and η Hyi (in the West). If the conditions are excellent, one can also see on this level ζ Hyi in the East, with the top of ε, and π Hyi in the center, the top of δ. The unit marks the mouth of the hydre.
While continuing always more in the South, after still ~5°, one finds with the SE γ Hyi, in the alignment of α towards ε, and 10° more in the South β Hyi, in the alignment of α towards η Hyi. These two stars are the tentacles of the hydre.
The small cloud of Magellan is located on alignment between α and β Hyi, with ~5° in the north of β Hyi; but the limits of the constellations are such as it is entirely included/understood in the constellation of the Toucan. In fact, the limits of Hydre are so angular that the three edges of its principal triangle, which connects α and β and γ Hyi, leave all the three the constellation.
Principal stars
See also: List of stars of male Hydre
β Hydri
β Hydri, the most brilliant star of the constellation with a Magnitude connects of 2,82, resembles the Sun much: it is a star of the principal Séquence orange, just a little hotter (and 3 times more brilliant).
It is also a star close to our Solar system, with 24,3 light-years.
β Hydri is the star nearest to the celestial south pole which is relatively luminous; it is isolated of 12° approximately.
Other stars
α Hydri (sometimes called the Head of Hydre ) is a star of the principal sequence magnitude connect 2,86.
γ Hydri is a giantess red apart 215 years light.
π Hydri is a star doubles visual with almost discernible components with the naked eye for an observer equipped with an excellent sight.
Celestial objects
Although surrounded by the Toucan, the Table and Sea-bream and located consequently between the Clouds of Magellan, the constellation of male Hydre contains only few celestial objects. One finds there the Galaxie S NGC 1473, NGC 1511 and NGC 1717 and the Nébuleuse NGC 602.
See too
- List of stars of male Hydre
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