The earliest, and perhaps most important of Ptolemy's work that has survived is the Almagest, a treatise in 13 books. It gives in detail the mathematical theory of the motions of the Sun, Moon, and planets. Ptolemy made his most original contribution by presenting details for the motions of each of the planets.
Also question is, what is Ptolemy best known for?
Ptolemy, Latin in full Claudius Ptolemaeus (fl. AD 127-145, Alexandria), ancient astronomer, geographer, and mathematician who considered the Earth the center of the universe (the "Ptolemaic system"). Virtually nothing is known about his life.
What did Ptolemy invent?
Ptolemy was an astronomer and mathematician. He believed that the Earth was the center of the Universe. The word for earth in Greek is geo, so we call this idea a "geocentric" theory.
What constellations did Ptolemy discover?
Ptolemy listed 1,028 objects forming the classical 48 constellations.
- Ursa Minor. Ursa Major.
- Draco. Cepheus.
- Boötes. Corona Borealis.
- Hercules. Lyra.
- Cygnus. Cassiopeia.
- Perseus. Auriga.
- Ophiuchus. Serpens.
- Sagitta. Aquila.