Hydra was set up by Claudius Ptolemy. It has an area of 1303 square degrees and 228 naked-eye stars. Claudius Ptolemy It is one of 48 constellation in the world.

It has the largest area of the 88 constellation that are present. It is long from east to west and the entire constellation area can be seen only in spring.

According to a legend, a crow was told by Apollo to bring a cup of wine from a spring on earth, and it waited for days for the figs to ripen so that it could eat them. The crow took the cup and a water snake from the spring and lied that the snake would use up all the water in the spring every day.

But Apollo knew the truth, and the raven was punished by being banished to the human world for a long time. It is said that Apollo made the raven, the cup, and the water serpent constellation as a warning against deceptive deeds to deceive the gods. However, the later constellation was to be the hydra, a nine-headed monster serpent that lived in the swamps of Lernae, which was vanquished by the hero Hercules.


[Source of story.
Hoshi no Bunka Shi Shi Jiten (Encyclopedia of the Cultural History of the Stars), Hakusuisha, Inc.
Zenten constellation Encyclopedia, Kawade Shobo Shinsha (February 2011)