Serpens (the Serpent or Snake) is a constellation located on the celestial equator. It is the only official constellation that is divided into two parts: Serpens Cauda (the Serpent's Tail) and Serpens Caput (the Serpent's Head). Its brightest star is Unukalhai, located in Serpens Caput.
Serpens the Serpent is virtually inseparable from Ophiuchus the Serpent Bearer, so it is rarely depicted as a stand-alone constellation, although Serpens Caput is sometimes depicted separately. It is represented by the two groups of straight lines extending from either side of Ophiuchus. The eastern part (to the left) is Serpens Cauda, represented by straight lines only, and the western part (to the right) is Serpens Caput, represented by several straight lines ending in a triangle. The east and west of the celestial sphere are mirrored because the sphere is observed from the inside.
