Hydra (constellation)

Hydra (constellation)

Infobox Constellation
name = Hydra
abbreviation = Hya
genitive = Hydrae
symbology = the sea serpent
RA = 8-15h
dec= −20
areatotal = 1303
arearank = 1st
numbermainstars = 17
numberbfstars = 75
numberstarsplanets = 6
numberbrightstars = 1
numbernearbystars = 2
brighteststarname = Alphard (α Hya)
starmagnitude = 1.98
neareststarname = HR 4458
stardistance = 31.1
numbermessierobjects = 3
meteorshowers =Alpha Hydrids
Sigma Hydrids
bordering =Antlia
Cancer
Canis Minor
Centaurus
Corvus
Crater
Leo
Libra
Lupus (corner)
Monoceros
Puppis
Pyxis
Sextans
Virgo
latmax = 54
latmin = 83
month = April
notes= |

Hydra (pronEng|ˈhaɪdrə) is the largest of the 88 modern constellations, and was also one of the 48 constellations listed by Ptolemy.

Notable features

Hydra is the largest modern constellation, at 1303 square degrees.Despite its size, Hydra contains only one reasonably bright star, Alphard (α Hya, 30 Hya), which is of apparent magnitude 1.98. Alphard ("the solitary one") is actually a double star. The other main named star in Hydra is Sigma, σ, Hydrae, which also has the name of Minaruja, from the Arabic for snake's nose. At magnitude 4.54, it is rather dim.

R Hydrae is a Mira variable star that ranges in magnitude between 3.5, when it can be visible to the naked eye, to 10.9, when a telescope is required to see it.

There are several double stars of interest in Hydra. Epsilon Hydrae (ε Hya) is a binary star with components of magnitudes 3.3 and 6.8, separated by 2.7 arcseconds. N Hydrae (N Hya) is a pair of stars of magnitudes 5.8 and 5.9. Struve 1270 (Σ1270) consists of a pair of stars, magnitudes 6.4 and 7.4.

The constellation also contains the radio source Hydra A.

Notable deep sky objects

The constellation Hydra contains three Messier objects. M83, also known as the Southern Pinwheel Galaxy, is located on the border of Hydra and Centaurus, M68 is a globular cluster near M83, and M48 is an open star cluster in the western end of the serpent.

Mythology

The constellation Hydra resembles a twisting snake, and features as such in some Greek myths. In Greek mythology, a crow serves Apollo. It is sent to fetch water, but it rests lazily on the journey, and after finally obtaining the water in a cup, takes back a water snake as well, as an excuse. According to the myth, Apollo saw through the fraud, and angrily cast the crow, cup, and snake, into the sky. The origin of this story is likely to be the juxtaposition of this constellation with those of Crater, and Corvus, in the area of the sky known as the Sea.

The Hydra was also considered to be the Lernaean Hydra (as defeated by Heracles for one of his Twelve Labours) by the Greeks. Its position in the sky (below the ecliptic), together with the constellation Cancer (which lies near its head) may be the origin of parts of the myth.

References

* Ian Ridpath and Wil Tirion (2007). "Stars and Planets Guide", Collins, London. ISBN 978-0007251209. Princeton University Press, Princeton. ISBN 978-0691135564.

External links

* [http://www.allthesky.com/constellations/hydra/ The Deep Photographic Guide to the Constellations: Hydra]
* [http://www.ianridpath.com/startales/hydra.htm Star Tales – Hydra]


Wikimedia Foundation. 2010.

Игры ⚽ Нужен реферат?

Look at other dictionaries:

  • Hydra — may refer to:* Lernaean Hydra, a mythological many headed serpent * hydra , an alternate spelling of the prefix hydro , referring to water. * The internet advertising company Hydra LLC, Hydra Network.It may also refer to:In science* Hydra… …   Wikipedia

  • Hydra Ichi — Infobox animanga character name = Hydra Ichi series = Saint Seiya caption = Ichi, the HydraBronze Saint, in a screenshot from the TenKaiHen Overture movie. creator = Masami Kurumada voiced by = Masato Hirano TV Masaya Onosaka OVA age = 14 gender …   Wikipedia

  • Constellation de l'Hydre — Hydre (constellation) Pour les articles homonymes, voir hydre. Hydre …   Wikipédia en Français

  • Hydra — [hī′drə] n. pl. for 3 & 4 Hydras, Hydrae [hī′drē΄] [ME ydre (< OFr < L), ydra < L Hydra < Gr, water serpent, akin to hydōr, WATER] 1. Gr. Myth. the nine headed serpent slain by Hercules as one of his twelve labors: when any one of its …   English World dictionary

  • Hydra — Hy dra, n.; pl. E. {Hydras}, L. {Hydr[ae]}. [L. hydra, Gr. y dra; akin to y dwr water. See {Otter} the animal, {Water}.] 1. (Class. Myth.) A serpent or monster in the lake or marsh of Lerna, in the Peloponnesus, represented as having many heads,… …   The Collaborative International Dictionary of English

  • Constellation — This article is about the star grouping. For other uses, see Constellation (disambiguation). The constellation Orion is one of the most recognizable in the night sky. In modern astronomy, a constellation is an internationally defined area of the… …   Wikipedia

  • Hydra Cluster — Galaxy cluster name = Hydra Cluster epoch = J2000 ra = RA|10|36.9cite web title=NASA/IPAC Extragalactic Database work=Results for Abell 2151 url=http://nedwww.ipac.caltech.edu/ accessdate=2007 07 19] dec = DEC| 27|32 dis ly = 158 Light Year dis… …   Wikipedia

  • hydra — /huy dreuh/, n., pl. hydras, hydrae / dree/ for 1 3, gen. hydrae / dree/ for 4. 1. (often cap.) Class. Myth. a water or marsh serpent with nine heads, each of which, if cut off, grew back as two; Hercules killed this serpent by cauterizing the… …   Universalium

  • Constellation Family — For East Asian and Chinese constellation groupings, see Chinese constellations. Constellation Families[1][2][3][4][3] (singularly as Constellation Family) …   Wikipedia

  • Hydra — I. noun Etymology: Middle English Ydra, from Latin Hydra, from Greek Date: 15th century 1. a many headed serpent or monster in Greek mythology that was slain by Hercules and each head of which when cut off was replaced by two others 2. not… …   New Collegiate Dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”