Don't have a watch? Well, no problem, at least at midnight as Hydra (or at least its head), is just about due South at 12 midnight. To see it, just go out, look South, and about a third of the way up from horizon to zenith (straight overhead). While it may not exactly ump out at you, there is an oval of stars that represents the snake's head. For the record, Hydra is the largest constellation in the sky, spanning over 100 angular degrees of sky.