Fixed bounds of v. broad faint S. constellation. Asterism as fem. snake. Delta (west) via Sig.-Eta-Epsilon-Rho loop, Omega Tau1,2 Iota Alpha Ups.1,2 Lambda Mu Phi Nu Xi Beta Gamma and Pi to E Hya. (far east)
Hydra (constellation) (Wikipedia)Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees, and also the longest at over 100 degrees. Its southern end borders Libra and Centaurus and its northern end borders Cancer. It was included among the 48 constellations listed by the 2nd century astronomer Ptolemy. Commonly represented as a water snake, it straddles the celestial equator.