The largest modern constellation , measuring 1303 square degrees is commonly represented as a water snake.Hydra has a extensive history having been listed in Ptolemy’s 48 constellations.Hydra is often confused with Hydrus- a constellation with almost a similar name.Right ascension and declination for Hydra is 8-15 h and -20° respectively.
It has seventeen main stars, 75 bayer stars and eighteen stars with planets.The most luminous star of Hydra is Alphard which has three times the mass of the sun and ages approximately 420 million.It represents the heart of the snake in the constellation.Hydra’s tail is in between the constellations of Centaurus and Libra whereas its head is in south of the constellation named Cancer.Greek constellation of Hydra is an adaption of the Babylonian constellation Mul.
Apin which corresponds to Hydra.In Greek mythology, it is associated with the monster Hydra, who had many heads and was put to death by Hercules.Hercules destroyed the roots of the head of Hydra so that they can’t grow again.
Another myth says that once a crow was given a cup by Apollo and was asked to serve him water.In his way, the crow saw a tree and stopped there for eating and spent a long time there.He knew that Apollo would be angry so he grabbed a water snake and told Apollo that the snake was blocking his way.Apollo already knew the matter and in anger, he gave the crows black feathers and a harsh voice.He also threw the crow, cup and the snake into the sky.In Japanese mythology, the stars are named as Nuriko whereas in Hindu mythology, the star that resemble Hydra is known as Ashlesha.
As mentioned earlier, Asphalt is the only brightest star ;however, the yellow colored star-Gamma Hydrae is the second most luminous star in the constellation and has a age of 372 million-slightly younger than the sun.Hydrobius and Beta Hydrae are at number three and four with respect to illumination in the constellation.Hydrobius is four hundred twenty (420) million years old, and has 4,2 times the mass of the Sun.The only confirmed planet in the constellation is the fifth brightest star named – HD 122430.Shining with an apparent magnitude of 5.47, this giant orange star is located four hundred and forty (440) light years away from Earth.Three Messier objects and a number of cluster objects, including star clusters and galaxies are present in this constellation.The only Messier object in Hydra was discovered by Charles Messier in 1971.It can be seen with binoculars in the northern hemisphere.With a visual magnitude of 5.5, this cluster is fifteen hundred years away from Earth.It approximately contains 80 stars and ages three hundred (300) million.The global cluster containing over two thousand stars (2000) discovered by Messier in 1780 is named as Messier 68.Being 33600 light years away with an apparent visual magnitude of 9.8, makes this sky object a difficult task for telescopes.One of the most luminous galaxy called Southern Pinwheel Galaxy is also present in the constellation of Hydra.It is just 14.7 million light years away and has a visual magnitude of 7.54.It was discovered by Nicolas Louis de Lacaille in 1752.There are two meteor showers that peak in Hydra during the months of December and january and are called Sigma hydrids and Alpha Hybrids.Hydra can be best seen in the month of April around 21:00 (9 pm).