Hydra

English name Hydra

Major
stars alpha Hydrae Alphard magn. 2,2 RA: 09h 27m 35.26s Dec: -08° 39' 31.2"
gamma Hydrae magn. 3,3 RA: 13h 18m 55.30s Dec: -23° 10' 17.5"
epsilon Hydrae magn. 3,5 RA: 08h 46m 46.61s Dec: +06° 25' 07.6"
zeta Hydrae magn. 3,3 RA: 08h 55m 23.64s Dec: +05° 56' 43.8"
ny Hydrae magn. 3,3 RA: 10h 49m 37.48s Dec: -16° 11' 37.6"
pi Hydrae magn. 3,5 RA: 14h 06m 22.29s Dec: -26° 40' 56.3"

Description Even though it is rather weak, Hydra is the biggest constellation of the sky, which extends for well seven hours of right ascension. The most evident part is a small group of stars that draw the head and that are on the border with Cancer, to the south-west of Leo: from there, the tail stretches toward Centaurus, finally touching Libra.
There are no very bright stars, except Alphard ("the solitary one", in Arab), an orange giant. Remarkable is also epsilon Hydrae, a double composed by a yellow star and a blue star, respectively of third and seventh magnitude.
M83 Among the other interesting heavenly objects there are: M48, an open cluster of about eighty stars, situated on the border with Monoceros; NGC 3242, a planetary nebula of ninth magnitude, known as Ghost of Jupiter because it resembles the planet Jupiter; M68, a globular cluster to observe with instruments of a certain power; and finally M83 (reproduced here on the right), a frontally seen spiral galaxy, among the brightest galaxies of the southern sky.

Mythology
and history The constellation represents the monstrous snake wiht nine heads (but in the sky it has only one head) that lived in the Lerna swamp, from which it went out to devastate the surrounding country. During the second of his labours, Hercules attached it: with the cudgel he broke its heads, but they immediately regrew in double number. Then the hero asked for help his coachman Iolao, who burned with an ardent brand the stump of every cut head. So the monster was defeated and killed.
Another legend associates this constellation with Crater and Corvus (see the mythology of this latter).

English name	Hydra

Major stars	alpha Hydrae	Alphard	magn. 2,2	RA: 09h 27m 35.26s	Dec: -08° 39' 31.2"
	gamma Hydrae		magn. 3,3	RA: 13h 18m 55.30s	Dec: -23° 10' 17.5"
	epsilon Hydrae		magn. 3,5	RA: 08h 46m 46.61s	Dec: +06° 25' 07.6"
	zeta Hydrae		magn. 3,3	RA: 08h 55m 23.64s	Dec: +05° 56' 43.8"
	ny Hydrae		magn. 3,3	RA: 10h 49m 37.48s	Dec: -16° 11' 37.6"
	pi Hydrae		magn. 3,5	RA: 14h 06m 22.29s	Dec: -26° 40' 56.3"

Description	Even though it is rather weak, Hydra is the biggest constellation of the sky, which extends for well seven hours of right ascension. The most evident part is a small group of stars that draw the head and that are on the border with Cancer, to the south-west of Leo: from there, the tail stretches toward Centaurus, finally touching Libra. There are no very bright stars, except Alphard ("the solitary one", in Arab), an orange giant. Remarkable is also epsilon Hydrae, a double composed by a yellow star and a blue star, respectively of third and seventh magnitude. Among the other interesting heavenly objects there are: M48, an open cluster of about eighty stars, situated on the border with Monoceros; NGC 3242, a planetary nebula of ninth magnitude, known as Ghost of Jupiter because it resembles the planet Jupiter; M68, a globular cluster to observe with instruments of a certain power; and finally M83 (reproduced here on the right), a frontally seen spiral galaxy, among the brightest galaxies of the southern sky.

Mythology and history	The constellation represents the monstrous snake wiht nine heads (but in the sky it has only one head) that lived in the Lerna swamp, from which it went out to devastate the surrounding country. During the second of his labours, Hercules attached it: with the cudgel he broke its heads, but they immediately regrew in double number. Then the hero asked for help his coachman Iolao, who burned with an ardent brand the stump of every cut head. So the monster was defeated and killed. Another legend associates this constellation with Crater and Corvus (see the mythology of this latter).

Hydra

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