Generalities: it is the only constellation to be divided into two non bordering parts . The most western part is the head of the Serpent (Serpens Caput), while the most eastern one is  the tail (Serpens Cauda). Both parts of this constellation are separated from the Ophiucus or Serpentarius. Both  stumps of this constellation master the celestial equator. The head of the Serpent is prominently in the northern sky, while the tail is  in the southern sky. The head transits  at the end of May, while the tail transits at the  beginning of July.

Origins and mythology: it represents the Serpent with which the Serpentarius (Ophiucus) is fighting.

Stars: in the head  an orange star of magnitude 2.65 (Unuk al-Hay) is present together with  other 5 stars under magnitude 4. In the tail less bright stars are present: only three stars are under magnitude 4. The brightest star of the tail is eta Serpentis, of orange color and magnitude 3.26.

Table of stars brighter than magnitude 3.5
 

Star	Proper name	Magnitude	Spectrum	Colour	Distance (light-years)	Notes
Alpha	Unuk al-Hay	2.65	K2	orange	85	in the head
Eta		3.26	K0	orange	52	in the head
Theta	Alya	3.4 (4.06+4.98)	A5+A5	white+white	101	in the tail - Visual double star

Other objects: in the head of the Serpent a nice globular cluster is present: M5. In the tail the nebula M16 is found, called Eagle Nebula.

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