Seleucus of Seleucia was an ancient astronomer who defended heliocentrism, arguing that Earth orbits the Sun and rotates on ...

Claudius Ptolemy was a Greek mathematician, astronomer and geographer who lived in the Egyptian city of Alexandria while under the rule of the Roman Empire. Much of medieval astronomy and ...

Cleostratus was a truly pioneering Greek astronomer who lived on the small Aegean island of Tenedos in the 6th century BC.

Around the second century C.E., the Greek astronomer Claudius Ptolemy listed 48 "official" constellations in his book Almagest. No original copy of Almagest has survived, so we don't know how he ...

Now researchers have managed to recover the text written by Ptolemy on a parchment that suffered such a previous recovery attempt. Outermost six rings of the meteoroscope, not to scale.

In accord with the Greek ideals of symmetry and harmony, geographer and astronomer Claudius Ptolemy declared that a great northern landmass must be balanced by a twin in the Southern Hemisphere.

An Egyptian astronomer called Ptolemy (AD100-168) described one of the earliest ideas for how the Solar System is structured. Ptolemy’s model and many earlier ideas of the Solar System had the ...

This so-called Geocentric model was the construction of famous Greek mathematician, astronomer Ptolemy. The model, though invaluable in helping to predict the positions of the stars and planets ...

helped overthrow more than a thousand years of Aristotelian thinking (reinforced by Greek astronomer Claudius Ptolemy) which said that objects only moved if an external force drove that motion.