Serpens

The sky is divided into 88 constellations. Actually, though, it’s more like 88 and a half. That’s because the constellation Serpens consists of two disconnected parts — a head and a tail. They’re separated by the serpent bearer as they wrap behind his body.
Serpens is in full view in the east and southeast by a couple of hours after sunset. The half that represents the head is highest, above Ophiuchus, with the tail below the serpent bearer.
The front half of the snake, Serpens Caput, is the more prominent one. It has several stars that are fairly easy to see. The brightest is Alpha Serpentis, also known as Unukalhai — “the serpent’s neck.” It’s a red giant — an old, bloated star that’s much bigger and brighter than the Sun. Its surface is much cooler than the Sun’s, so the star looks yellow-orange.
The back half of the snake, Serpens Cauda, is tougher to spot. Its brightest star, Eta Serpentis, is actually the second-brightest star in the whole constellation. It’s about half as bright