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Ptolemy's Almagest

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The main desire of Ptolemy in writing his Almagest is to explain and account for the motions of the apparently erratic celestial beings in terms of perfect and circular motions. In doing so he introduces the epicyclic (which states that the center of a smaller circle orbits around the earth and the object orbits around the smaller circle) and the eccentric hypotheses (which supposes that the center of the circular motion of the planet is not exactly centered on the earth), which are ultimatly equivalent to eachother in terms of result. Begining with the motion of the sun in the sky and moving on to the less accountable outer planets, Ptolemy moves his mathematics brilliantly with a nod to a story teller's art. Some may find his introduction of his equant (something that is often said to defile his principles of perfect motion), which explains the retrogradation of the outer planets, to be a let down to the fanfare of perfection in the stars. Yet, overall, the Almagest manages to recapture the magic and wonder of the universe through complicated mathematical hypotheses and to succesfully lay the ground for the break throughs of Copernicus, Brahe, and Kepler to come. If you are at all interested in astronomy or mathematics, you ought to read this.

Adding to the other comment below about star names beginning with "al-," I might add that the title "Almagest" itself is an Arabic translation of the original Greek "Megale Syntaxis."

It's a very interesting astronomy book, it's explain how they've thought about the motion of the planets(epicycles)in the past(AC)by the time of the Ptolemy and Babylonia.

The mathematics is difficult to follow, but as it is developed from Euclid and Eratosthenes it is reliable. The observations have been made from a very wide area and over a long time; but while the mechanics may be rather mysterious the results are impressive.

Does the front cover always show Penelope weaving at her loom? - the ancients obviously thought highly of Homer and the Greek myths.

The Tetrabiblos survives together with the parallel Greek. Since the Almagest went through successive transliterations/translations (and interpretations?), it might not be too surprising if the Greek text has disappeared.

And what of Ptolemy's other books? - his geography for example. The Almagest has observations from Ceylon to Thule, including Britain. The ancients must have travelled widely.

Is there anywhere an account of the origin of the names of stars and constellations? These seem to have accumulated over time. Many star names begin "Al-", from the Arabic, I suppose.

Well done!

so it turns out that the center of the eccentric circle that the planets travel on travels on its own circle but be careful this is not a giant epicycle on a small deferent! haha! genius!!