For the ancient Greeks, the night sky was a picture book depicting scenes from their mythology. Getting to know the constellations can bring those myths to life today.

There’s nothing quite as awe-inducing at the sky on a clear summer’s night. If you live in an urban area, these nights are the exception; a haze of cloud and light pollution being the rule. But every so often, the curtain falls on the day to reveal a black sky glittering with stars.

When this happens, I’m always struck with the fact of my own smallness – the realisation that all our human dramas are just a blip in the impossible magnitude of space. I’m also struck by my connectedness to other people in other times. On the face of things, I might not have that much in common with a Neolithic farmer in ancient Britain, or a hunter-gatherer on the African savanna. But they too would have looked up at the sky – most likely a clearer, brighter sky – to see this very same array of stars.

This is not to say that all people everywhere would have parsed up the sky in the same way. For one thing, the stars will shift depending on the time of year, or where you are in the world. For another thing, since the stars themselves are in motion, the outline of each constellation will morph beyond recognition over a period of thousands of years.

On top of that, different civilisations would have projected their own imaginings on the stars. I might look at the sky right now and, playing a game of join the dots, see an aeroplane or a double helix or a mobile phone. Someone living 5,000 years ago might notice a hand axe or a harpoon.

That means there’s nothing inevitable about the existence of Ursa Major or Orion’s Belt. The standardised list of constellations we have today – a list of 88 groupings agreed by the International Astronomical Union (IAU) in 1922 – could easily have been otherwise. But the fact we do see Ursa Major and Orion tells us a lot about the myths that have gone the distance; each constellation a piece of history crystallised in the sky.

Ian Ridpath, a well-known astronomy writer and lecturer, remarks there were probably several different reasons for the invention of constellations. “The earliest of them were probably devised for practical purposes, such as to help seafarers and other travellers find directions at night,” he says. “Another purpose, more social than practical, was to act as a picture book to illustrate scenes and characters from mythology.”

The constellations we recognise today originated in the Middle East around the second millennium BCE. The ancient Greeks took these groupings and adapted and expanded them, culminating in the Almagest by Ptolemy – an astronomical treatise cataloguing 48 constellations. Each constellation, according to the Greeks, was placed there by the gods to honour to those who had performed great deeds on earth.

“Back then no one knew what stars were, or how far away they were. Stars were regarded simply as lights hanging on a sphere that rotated around the Earth every day,” says Ridpath.

For those of us in the northern hemisphere, a good place to start might be the Summer Triangle, consisting of the bright stars Vega, Deneb, and Altair in the constellations Cygnus, Lyra, and Aquila. It should be noted that the Summer Triangle itself is not a constellation but an asterism – an unofficial, though easily recognisable, grouping of stars.

Lyra represents the lyre (or harp) of Orpheus, a mortal man who was gifted with incredible musical powers. Crazed with grief after the death of his bride, he aimlessly wandered the hills strumming his lyre. After his death, the gods placed his magical harp in the sky.

Aquila, which means ‘the eagle’ in Latin, has several associated myths. In one story, the eagle held Zeus’ thunderbolts; in another, the eagle was the love goddess Aphrodite in disguise. In another, the eagle kidnapped a prince called Ganymede; in yet another, the eagle was found guarding the arrow of Eros that struck Zeus.

Then there’s Cygnus, Ridpath’s personal summer favourite. “It lies almost overhead during summer months, and appears to fly along the starry band of the Milky Way,” he says. “It is also known as the Northern Cross since its main stars form an easily recognised cross shape, far bigger and better than the more famous southern cross. In mythology it represents a disguise of Zeus (another one!) that he adopted to seduce Queen Leda of Sparta.”

Another important summer constellation is Hercules, the fifth largest constellation in the sky. Unsurprisingly, it is named after Hercules – the Roman name for the Greek hero Heracles. He was the son of Zeus and a mortal woman, who was known for killing Ladon the Dragon. The dragon in question is represented by the neighbouring constellation Draco, which is visible all year round.

Over the summer months, you might also catch a glimpse of two constellations of the zodiac – Scorpius and Sagittarius. As Ridpath explains, the constellations of the zodiac are those through which the sun appears to pass every year. “The astrological signs do not coincide with the astronomical constellations and the two should not be confused,” he adds.

Scorpius looks distinctively like a scorpion, with the bright red star Antares at its heart. In Greek mythology, it was the giant scorpion sent by the earth goddess Gaia to slay the hunter Orion.

Sagittarius, meanwhile, means ‘archer’ – even though to many modern observers, it looks more like a teapot. It is associated with the myth of Chiron, a centaur who acted as a teacher to many Greek heroes. The centaur was immortalised in the sky, shooting a bow and arrow into the heart of Scorpius.

“The old myths live on, and you can see them illustrated every night in the sky as constellations of stars,” says Ridpath. “Learning about the myths of the constellations gives us a real connection with the ancient civilisations who first devised those pictures in the sky.”

This article appears in the June-Sept 2023 edition of Overseas