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 ...

In astronomy, what does retrograde mean? And what connection does it have to astrology? We explain how planets move across ...

More recently, a manuscript once thought to be penned by Claudius Ptolemy, the renowned Egyptian mathematician and astronomer of Greek descent, has been deciphered. The ancient text, dating back ...

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 ...