Serpens is an oddity: the only constellation interrupted by another. Half way down the serpent it crosses Ophiuchus and finishes on the other side of this constellation. The western half is ‘Serpens Caput’, or the Head of the Serpent, the eastern part is ‘Serpens Cauda’, the Tail of the Serpent.

There's a good reason that the Serpent has been interrupted by Ophiuchus, for Ophiuchus is known as ‘the serpent holder’. He was also a mythical healer, an ancient medical man. Thus together the two constellations show Ophiuchus grasping the serpent.

In fact this whole scene has become the symbol for modern medicine, the caduceus, a staff with two winding snakes.

And so when we study Serpens we'll also have to recognise at least part of Ophiuchus.

The constellation has some fine binaries as well as two Messier objects.

Prerequisite: Ophiuchus.

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