Hydra is known as the biggest modern constellation , measuring 1303 square degrees is commonly represented as a water snake.Hydra has a vast history having been listed in Ptolemy’s 48 constellations.It is considered an ancient constellation because it dates back to Babylonian civilization which had a similar constellation called the Mush.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 and known star of Hydra is Alphard which has thrice the mass of the sun and ages approximately 420 million.It shows the heart of the snake in the constellation..It belongs to the Hercules family of constellations along with many other constellations.
Hydra’s tail is in middle of the constellations of Centaurus and Libra whereas its head is in south of the constellation named Cancer.Other constellations which Hydra borders are Antlia, Monocerus, Lupus, Pyxis, Virgo, Libra etc.(A picture of hydra constellation)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-lived near the town of Lerna, and was damaging the countryside was put to death by Hercules.Hercules destroyed the roots of the head of Hydra so that they can’t grow again and arose the winner.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 was already familiar with the matter and in anger, he gave the crows black feathers and a harsh voice.He also threw the snake, crow and the cup 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 life 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 approved planet in the constellation is also 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.
Other notable stars include Gliese 433, Ry Hydrae, Delta Hydrae , 58 Hydrae etc.Three Messier objects and a number of cluster objects, including star clusters and galaxies are present in this constellation. Messier 68 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.Apart from these, there are many other galaxies present in the constellation of Hydra including Hydra Galaxy Cluster, Ghost of Jupiter, Tombaugh’s Globular Cluster etc.There are two meteor showers that peak in Hydra during the months of December and january and are called Sigma Hydrids and Alpha Hydrids.January 15-30 runs the Alpha Hydrids and around 20th January, almost 10 meteors can be seen per hour.Sigma Hydrids run in December from 5th to 15th with 11th being there peak when 5 meteors per hour are yield.( A map of the constellation of Hydra)Hydra can be seen easily and the best in the month of April around 21:00 (9pm).It is present in the southern sky and is just beneath the planet named Jupiter and goes throughout the southeast crossing the full southern sky.It is easy to locate, if we can found the brightest star of the constellation- Alphard.Hydra may not be clear but can be seen in this month and can be located outside.Sources-1 https://en.wikipedia.org/wiki/Hydra_(constellation)-2 http://www.astronomytrek.com/hydra-the-night-skys-largest-constellation-3 http://www.constellation-guide.com/constellation-list/hydra-constellation-4 https://stardate.org/radio/program/naughty-crow-5 https://www.revolvy.com/main/index.php?s=Hydra%20(constellation