# Almagest

**cataloghis book on astronomyMagna SyntaxisPlanetary HypothesesPtolemaicPtolemaic cosmologyPtolemyPtolemy's ''Almageststar catalog of PtolemyThe star catalog**

The Almagest is a 2nd-century Greek-language mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy (c. undefined AD 100 – c. 170).wikipedia

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### Ancient Greek astronomy

**Greek astronomyGreek astronomerastronomy**

The Almagest is a 2nd-century Greek-language mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy (c.

Later, the scientific work by astronomers and mathematicians of the arbo-moslem empire, of diverse backgrounds and religions (such as the Syriac Christians), to translate, comment and then correct Ptolemy's Almagest, influenced in their turn Indian and Western European astronomy.

### Ptolemy

**Claudius PtolemyClaudius PtolemaeusPtolemaic**

The Almagest is a 2nd-century Greek-language mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy (c.

The first is the astronomical treatise now known as the Almagest, although it was originally entitled the Mathematical Treatise (Μαθηματικὴ Σύνταξις, Mathēmatikē Syntaxis) and then known as the Great Treatise (Ἡ Μεγάλη Σύνταξις, Hē Megálē Syntaxis).

### Geocentric model

**geocentricPtolemaic systemPtolemaic**

170). One of the most influential scientific texts of all time, it canonized a geocentric model of the Universe that was accepted for more than 1200 years from its origin in Hellenistic Alexandria, in the medieval Byzantine and Islamic worlds, and in Western Europe through the Middle Ages and early Renaissance until Copernicus.

His main astronomical work, the Almagest, was the culmination of centuries of work by Hellenic, Hellenistic and Babylonian astronomers.

### Ptolemy's table of chords

**table of chordshis table of chordscalculation of chords**

The table of chords, created by the Greek astronomer, geometer, and geographer Ptolemy in Egypt during the 2nd century AD, is a trigonometric table in Book I, chapter 11 of Ptolemy's Almagest, a treatise on mathematical astronomy.

### Planet

**planetsFormer classification of planetsplanemo**

The Almagest is a 2nd-century Greek-language mathematical and astronomical treatise on the apparent motions of the stars and planetary paths, written by Claudius Ptolemy (c.

These theories would reach their fullest expression in the Almagest written by Ptolemy in the 2nd century CE.

### Constellation

**constellationsEuropean constellationModern constellation**

They are given in Aratus' work Phenomena and Ptolemy's Almagest, though their origin probably predates these works by several centuries.

### Star catalogue

**star catalogNLTTLHS**

90 – c. 186 AD) of Roman Egypt published a star catalogue as part of his Almagest, which listed 1,022 stars visible from Alexandria.

### Apparent magnitude

**apparent visual magnitudemagnitudevisual magnitude**

This rather crude scale for the brightness of stars was popularized by Ptolemy in his Almagest and is generally believed to have originated with Hipparchus.

### Zodiac

**signs of the zodiactropical zodiaczodiacal signs**

The construction of the zodiac is described in Ptolemy's vast 2nd century AD work, the Almagest.

### Chord (geometry)

**chordchords chord**

In the second century AD, Ptolemy of Alexandria compiled a more extensive table of chords in his book on astronomy, giving the value of the chord for angles ranging from 1/2 degree to 180 degrees by increments of half a degree.

### Middle Ages

**medievalmediaevalmedieval Europe**

170). One of the most influential scientific texts of all time, it canonized a geocentric model of the Universe that was accepted for more than 1200 years from its origin in Hellenistic Alexandria, in the medieval Byzantine and Islamic worlds, and in Western Europe through the Middle Ages and early Renaissance until Copernicus.

Astronomy advanced following the translation of Ptolemy's Almagest from Greek into Latin in the late 12th century.

### Fixed stars

**fixed starfixedstars**

Ptolemy was influential with his heavily mathematical work, The Almagest, which attempts to explain the peculiarity of stars that moved.

### Nicolaus Copernicus

**CopernicusCopernicanNicholas Copernicus**

170). One of the most influential scientific texts of all time, it canonized a geocentric model of the Universe that was accepted for more than 1200 years from its origin in Hellenistic Alexandria, in the medieval Byzantine and Islamic worlds, and in Western Europe through the Middle Ages and early Renaissance until Copernicus.

The prevailing theory in Europe during Copernicus's lifetime was the one that Ptolemy published in his Almagest c.

### Gerard of Cremona

**Gerardus CremonensisGerard of CremoneGerard**

Gerard of Cremona, who translated an Arabic manuscript into Latin around 1175, put 300° for the latitude of several stars.

One of Gerard's most famous translations is of Ptolemy's Almagest from Arabic texts found in Toledo.

### Hipparchus

**HipparchosHipparchus of NicaeaHipparchus of Nicea**

He states that he found that the longitudes had increased by 2° 40′ since the time of Hipparchos.

Most of what is known about Hipparchus comes from Strabo's Geography and Pliny's Natural History in the 1st century; Ptolemy's 2nd-century Almagest; and additional references to him in the 4th century by Pappus and Theon of Alexandria in their commentaries on the Almagest.

### Axial precession

**precession of the equinoxesprecessionprecession of equinoxes**

This is the amount of axial precession that occurred between the time of Hipparchos and 58 AD.

According to Ptolemy's Almagest, Hipparchus measured the longitude of Spica and other bright stars.

### Deferent and epicycle

**epicyclesdeferentdeferents and epicycles**

262 – c. 190 BC) had introduced the deferent and epicycle and the eccentric deferent to astronomy.

It was developed by Apollonius of Perga and Hipparchus of Rhodes, who used it extensively, during the 2nd century BC, then formalized and extensively used by Ptolemy of Thebaid in his 2nd century AD astronomical treatise the Almagest.

### Celestial spheres

**celestial sphereplanetary spherescelestial**

Ptolemy assigned the following order to the planetary spheres, beginning with the innermost:

In his Almagest, the astronomer Ptolemy (fl.

### Venus

**Morning Starevening starplanet Venus**

In the second century, in his astronomical treatise Almagest, Ptolemy theorized that both Mercury and Venus are located between the Sun and the Earth.

### Jupiter

**JovianGioveplanet Jupiter**

In his 2nd century work the Almagest, the Hellenistic astronomer Claudius Ptolemaeus constructed a geocentric planetary model based on deferents and epicycles to explain Jupiter's motion relative to Earth, giving its orbital period around Earth as 4332.38 days, or 11.86 years.

### St. John's College (Annapolis/Santa Fe)

**St. John's CollegeSt. John's College, AnnapolisSt. John’s College**

The first, by R. Catesby Taliaferro of St. John's College in Annapolis, Maryland, was included in volume 16 of the Great Books of the Western World in 1952.

They were sold to the general public as well as to students, and by 1941 the St. John's College bookshop was famous as the only source for English translations of works such as Copernicus's De revolutionibus orbium coelestium, St. Augustine's De Musica, and Ptolemy's Almagest.

### Alpha Centauri

**Alpha Centauri BAlpha Centauri Aα Centauri**

A series of stars in Centaurus are off by a couple degrees, including the star we call Alpha Centauri.

Alpha Centauri is listed in the 2nd-century star catalog of Ptolemy.

### R. Catesby Taliaferro

**Taliaferro, R. Catesby**

The first, by R. Catesby Taliaferro of St. John's College in Annapolis, Maryland, was included in volume 16 of the Great Books of the Western World in 1952.

He translated from Greek and Latin into English: Ptolemy's Almagest, a 2nd-century book on astronomy, the 13 books of Euclid's Elements, Apollonius' works on conic sections, and some works of Plato (Timaios, Critias), and St. Augustine (On Music).

### History of astronomy

**astronomyhistorian of astronomyBabylonians**

Hipparchus had some knowledge of Mesopotamian astronomy, and he felt that Greek models should match those of the Babylonians in accuracy.

Depending on the historian's viewpoint, the acme or corruption of physical Greek astronomy is seen with Ptolemy of Alexandria, who wrote the classic comprehensive presentation of geocentric astronomy, the Megale Syntaxis (Great Synthesis), better known by its Arabic title Almagest, which had a lasting effect on astronomy up to the Renaissance.

### Regiomontanus

**Johannes RegiomontanusJohannes MüllerJohann Müller of Königsberg**

The German astronomer Johannes Müller (known, from his birthplace of Königsberg, as Regiomontanus) made an abridged Latin version at the instigation of the Greek churchman Johannes, Cardinal Bessarion.

George of Trebizond who was Bessarion's philosophical rival had recently produced a new Latin translation of Ptolemy's Almagest from the Greek, which Bessarion, correctly, regarded as inaccurate and badly translated, so he asked Peuerbach to produce a new one.