The Ancient Greeks, like many other civilisations, looked up at the night sky and saw patterns in the stars. They identified 48 'constellations'. Because we inherited much of the learning of the Greeks, we still use almost all of these constellations today.
The Greek philosopher1 Hipparchos, in the 2nd century BC, decided to catalogue the stars, dividing them up into constellations, and making a note of the brightness of each star. His original catalogue is lost, but we have two other records of the stars from ancient times which appear to be based on it.
The oldest map of the constellations that has yet been found is the Farnese Atlas, a statue of the mythological giant, Atlas, who was forced to hold the heavens on his shoulders. This is now in the Naples Archaeological Museum. On this particular statue, the heavens were represented by a globe, which is carved with pictures of the constellations – the individual stars are not marked on the globe. Unfortunately, scholars can't agree on the exact date of the statue - some say it is based on Hipparchos's star catalogue, others deny this.
More useful is the star catalogue by Alexandrian astronomer Ptolemy, published in about 150 AD in his book The Almagest. This lists about 1,000 stars, giving their exact positions and brightnesses. This appears to be based on Hipparchos's work, but has been expanded to include some stars that are visible from Ptolemy's location of Alexandria which would not be visible by Hipparchos.
Ptolemy describes the 48 constellations, but many of the fainter stars are not included in any constellation. They lie outside the constellations. Although the catalogue does not include any pictures, it describes each star carefully in terms of its position in the constellation: the lower forearm, behind the head etc.
Ptolemy only described stars that were visible from Alexandria at the time. This included about 93% of the night sky, but there was about 7% which was not visible2 due to being too far south.
All of Ptolemy's constellations except one are still used today, although some have different names. The one exception is the constellation Argo, which was considered too big by modern astronomers, so it was split into three (or possibly four) new constellations.
Here's the list. They're presented in the order Ptolemy listed them in his catalogue, starting at the north ecliptic pole and working down to the south ecliptic pole. All the Greek names are in genitive form, as they each had the word 'asterismos' (constellation) after them, for example 'Taurou asterismos', the constellation of the bull. Unfortunately I don't speak ancient Greek so I can't deduce the nominative form from this.
[Note: the transliteration of the ancient Greek into Roman letters is pretty self-evident. ê is eta and ô is omega.]
|Ptolemy's Name||Meaning||Our Name||Description/Comments|
|1||Arktou mikras||Small Bear||Ursa Minor||Shown with a long tail.|
|2||Arktou megalês||Big Bear||Ursa Major||Shown with a long tail|
|4||Kêpheôs||Cepheus, a person's name||Cepheus||Cepheus wears a tiara - the conical hat with a rounded top of a Persian king.|
|5||Boôtou||Herdsman||Boötes||The herdsman carried a club.|
|6||Stephanou boreiou||Northern Crown||Corona Borealis|
|7||Tou en gonasin||Figure on its Knees||Hercules||The figure was not specifically identified as Hercules.|
|8||Lyras||Lyre||Lyra||The lyre is made from a turtle shell.|
|9||Ornithos||Bird||Cygnus||Ptolemy doesn't specify that this is a swan, just a bird, but it is a bird with a very long neck.|
|10||Kassiepeias||Cassiopeia, a person's name||Cassiopeia|
|11||Perseôs||Perseus, a person's name||Perseus||Perseus holds the head of the Gorgon in his hand.|
|12||Hêniochou||Charioteer||Auriga||The charioteer carries a female goat and two kids.|
|14||Ophêos Ophiouchou||Snake of the Snake Carrier||Serpens|
|18||Hippou protomês||Front of a Horse||Equuleus|
|19||Hippou||Horse||Pegasus||Although this constellation is called 'Horse', it is decribed as having wings, so it clearly is Pegasus, the mythical winged horse.|
|20||Andromedas||Andromeda, a person's name||Andromeda|
|23||*||Taurou||Bull||Taurus||The constellation is only the front half of a bull.|
|28||*||Chêlôn||Claws (of the Scorpion)||Libra||Although Ptolemy lists this as 'The Claws (of Scorpius)', he uses the term Zygos (meaning Libra) in some parts of the catalogue.|
|30||*||Toxotou||Archer||Sagittarius||The archer is shown as a centaur.|
|31||*||Aigokerô||Goat Sea Animal||Capricornus||This creature has horns, front legs and a fish's tail.|
|33||*||Ichthyôn||Fishes||Pisces||The fishes are shown caught on two fishing lines which are tied together with a knot.|
|34||Kêtous||Large Sea Animal, Whale||Cetus|
|35||Ôriônos||Orion, a person's name||Orion|
|36||Potamou||River||Eridanus||The river is un-named.|
|38||Kynos||Dog||Canis Major||The name 'Dog' applies both to the constellation and to the brightest star.|
|39||Prokynos||Pre-Dog||Canis Minor||This constellation had only two stars in it. It was called 'pre-dog' because it rose before the 'Dog'. The main star in the constellation had the same name as the constellation, Prokyon, and still bears this name. The description of the two stars talks about a neck and a back, so it is perhaps intended to represent another dog, as in the modern constellation.|
|40||Argous||Argo||Vela, Carina and Puppis||The Argo was the ship of Jason which sailed in search of the Golden Fleece. From Greece, this constellation would never have risen high above the horizon, so it might have looked like a ship hovering over the sea. On the other hand, only the back half of a ship is depicted.|
|41||Hydrou||Water Snake||Hydra||The ancient water snake was male rather than female. Nowadays we have another male water snake, Hydrus, in a part of the sky not visible from Greece.|
|42||Kratêros||Bowl for mixing wine with water||Crater|
|44||Kentauros||Centaur||Centaurus||The centaur was shown carrying a thyrsis, a stick with olive leaves on it which was a symbol of Dionysus. He also had a cloak with epaulets which are shown streaming back in the wind.|
|45||Thêriou||Beast||Lupus||Lupus is not identified as a wolf, just as a beast.|
|46||Thymiatêriou||Incense Burner||Ara||The modern Ara is an altar. The ancient one was just the incense burner from the altar.|
|47||Stephanou notiou||Southern Crown||Corona Australis|
|48||Ichthyos notiou||Southern fish||Piscis Austrinus|
* Constellation of the Zodiac
Pinkish entries are ones where the Greek constellation is not the exact equivalent of the modern one.
Some stars were shared between two different constellations. The star we now call Beta Tauri, for example, was considered to be part of both Auriga and Taurus and was listed in the catalogue twice. There are quite a few such shared stars. The most notable other one was the star we call Alpha Andromedae, which was considered to be a part of both Andromeda and Pegasus.
Ptolemy's Almagest is mainly concerned with calculating the positions of the sun, moon and stars. He shows little interest in the fixed stars. Some feel that his star catalogue was not even based on his own observations but was just reproduced from some other astronomer, probably Hipparchos.
Very few stars are given names in the catalogue. In fact, only 11 individual stars are named. This doesn't even include all the first magnitude stars, of which there are 21, all of them visible from Alexandria. In the following table, I've classified the names into ones which are the same as the modern name, one where our modern name is a translation into Latin of Ptoemy's Greek name, and ones where the modern name is different. Note that for some of the "same" names, the spelling is slightly different.
|Ptolemy's Name||Meaning||Our Name||Type||Description/Comments|
|Arktouros||Bear watcher||Arcturus||Same||Guards the sky against the Great Bear|
|Antarês||Against Ares||Antares||Same||The red colour of this star rivals the planet Ares (Mars)|
|Prokyôn||Pre-dog||Procyon||Same||Although further east than 'the Dog', it normally rises slightly earlier due to being further north.|
|Aix||Nanny-goat||Capella||Translation||Capella is the literal translation into Latin of Aix|
|Protrygêtêr||Bringer of vintage||Vindemiatrix||Translation|
|Stachys||Ear of corn||Spica||Translation|
|Lyra||The Lyre||Vega||Different||Our name comes from Arabic and means 'The Swooping (Eagle)'|
|Aetos||Eagle||Altair||Different||This was just called the Eagle. The Arabs later introduced a second eagle, so this became known as 'Al Tair', the 'Flying One'.|
|Kyôn||Dog||Sirius||Different||The star was sometimes called 'Kyôn Seirios', the scorching dog. Our name Sirius comes from this.|