Hydra (constellation)
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Its head lies south of Cancer, while its tail ends between Libra and Centaurus.[1] Covering 1303 square degrees and extending more than 100 degrees, Hydra is the largest among the 88 modern constellations.[2]
Key facts and history
The 2nd-century astronomer Ptolemy listed Hydra among his 48 constellations.[2][1] Eratosthenes and Ptolemy used the male name Hydros, but Aratus correctly used the feminine form Hydra.[1] In Chinese astronomy, the stars of Hydra's head formed the lunar mansion Liu, marking the head of the Red Bird of the South.[1] The constellation contains only one moderately bright star, Alphard (Alpha Hydrae), an orange giant of magnitude 2.0 located 177 light-years from Earth.[3]
Hercules' nephew Iolaus prevented regrowth by searing the necks of the heads with a torch, which allowed Hercules to defeat the creature.[4][1]
What the cited sources add
Johann Bode's 1801 atlas gave Hydra the alternative name Serpens Aquaticus.[1] Allen's Star Names records that early astronomers sometimes divided Hydra into four separate divisions, including Hydra et Crater and Continuatio Hydrae.[5] A uranographic stone from the Euphrates of 1200 BC shows a snake identified with the great dragon Tiāmat.[5]
References
- Ridpath, Ian. Star Tales Hydra. Retrieved 2018-12-28.. facts only, no text reused. ianridpath.com
- Wikipedia, "Hydra (constellation)" (CC BY-SA 4.0), which cites: Ridpath Tirion 2001, p. 158–160 (original not read by us) en.wikipedia.org
- Wikipedia, "Hydra (constellation)" (CC BY-SA 4.0), which cites: Ridpath, Ian. Star Tales Hydra. Retrieved 2018-12-28. (we also read that source) en.wikipedia.org
- Wikipedia, "Hydra (constellation)" (CC BY-SA 4.0), which cites: P.K. Chen (2007) A Constellation Album: Stars and Mythology of the Night Sky, p. 44 ( ). (original not read by us) en.wikipedia.org
- "LacusCurtius • Allen's Star Names — Hydra", penelope.uchicago.edu. facts only, no text reused. penelope.uchicago.edu
Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Hydra (constellation) (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.
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Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Hydra (constellation) (CC BY-SA 4.0).
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