The sky
Where star names come from
Most constellation names are Greek or Latin, and most bright star names are Arabic. Here is the real history of how that happened.
Look up at Orion and you are reading a Greek picture, labelled in Arabic, written down in Latin, and now read in English. Four cultures, one patch of sky. Here is how that happened.
The Greeks drew the pictures
Babylonian and Greek skywatchers grouped the stars into the figures we still use. Around 150 AD an astronomer named Ptolemy, working in Alexandria, gathered all of it into one book that listed 48 constellations and more than a thousand stars. That book is the reason so many constellations carry Greek and Latin names, like Orion the hunter, Leo the lion and Ursa Major the great bear.
The Arabic Golden Age kept it alive
As the Greek world declined, much of this knowledge could have been lost. Instead, from roughly the 8th to the 14th century, scholars across the Arabic-speaking world, from Baghdad to Córdoba, translated Ptolemy into Arabic, tested his measurements against their own, and built sharper star catalogues of their own. The astronomer al-Sufi finished his Book of the Fixed Stars around 964 AD, describing each star by its brightness and its place on the old mythological figure. An Arabic phrase for “the shoulder of the giant” or “the follower” slowly became the everyday name of a star.
The names crossed into Europe
From about the 12th century, European scholars began translating these Arabic works into Latin. The star names came with them, often scrambled by centuries of copying between alphabets. That is why the brightest single stars have Arabic roots: Betelgeuse from a phrase for the hand of the giant, Aldebaran the follower, Rigel the foot, Altair the flying one, Vega the swooping one, Deneb the tail, and Fomalhaut the mouth of the fish. Even the name of Ptolemy’s surviving catalogue, the Almagest, is half Arabic, from al-majisti, meaning the greatest.
Two layers, one sky
So the sky comes in two layers. The figures are mostly Greek. The individual stars are mostly Arabic. Nobody sat down and designed it that way. It is just the fingerprint of everyone who kept looking up and writing it down, handed from one language to the next for two thousand years.
Questions
Why are so many star names Arabic?
Because astronomers in the medieval Arabic-speaking world preserved and extended Greek astronomy for centuries, and their names for the brightest stars were carried into Latin and then English when Europe translated their work.
Are the constellations Arabic too?
Mostly not. The constellation figures came from the Greeks and Babylonians, so they kept Greek and Latin names like Orion and Leo. It is the individual bright stars inside them that tend to have Arabic names.
Sources: Ptolemy, Almagest, around 150 AD. al-Sufi, Book of the Fixed Stars, 964 AD. Paul Kunitzsch, scholarship on the Arabic origins of star names.