Serpens
The serpent coiling across the sky
Best on June–August evenings · celestial equator (visible from both hemispheres).
Serpens is the only constellation split into two separate pieces — Serpens Caput (the head) to the west and Serpens Cauda (the tail) to the east — divided by Ophiuchus, the serpent bearer, in the middle. It sprawls along the celestial equator, making it reachable from both hemispheres. Unukalhai marks the serpent's neck and is the brightest star to hunt for.
How to find it
On summer evenings, look for the bright keystone of Hercules high in the northern sky, then drop south toward the bright orange star Arcturus in Boötes — Serpens Caput lies between them, with Unukalhai as the brightest point in that region. Serpens Cauda trails off to the east of Ophiuchus, near the star-rich heart of the Milky Way; both halves are well placed from June through August for observers in either hemisphere.
Brightest stars
Orange giant Unukalhai (α Ser) leads at magnitude 2.65, the serpent's brightest gem and easy to pick out. Chow (β Ser) follows at magnitude 3.67, with Alya (θ¹ Ser) further back at 4.62.
Worth seeing
Unukalhai itself is the reward — a distinctly warm orange color that stands out nicely against the surrounding summer stars, and a reliable anchor for tracing the serpent's winding path across the sky.
Frequently asked
When is Serpens visible?
Summer evenings, roughly June through August, when it climbs well clear of the horizon. Because it sits on the celestial equator, observers in both the northern and southern hemispheres can catch it.
What are the main stars in Serpens?
Unukalhai (α Ser) at magnitude 2.65 is the brightest, marking the serpent's neck. Chow (β Ser) at 3.67 and Alya (θ¹ Ser) at 4.62 are the other named stars in the pattern.
Why is Serpens split in two?
Ophiuchus, the serpent bearer, stands in the middle of the constellation, dividing it into Serpens Caput (the head, to the west) and Serpens Cauda (the tail, to the east) — making Serpens the only constellation officially split into two separate parts.
Nearby constellations
Ophiuchus · Libra · Hercules · Scorpius · Boötes · Lyra · Aquila · Virgo