The star catalog of Hipparchus ( 2nd century BC ) included 1020 stars and was used to assemble Ptolemy's star catalogue.

Ptolemy's catalogue was based almost entirely on an earlier one by Hipparchus ( Newton 1977 ; Rawlins 1982 ).

The serious errors which he found in previous Arabian star catalogues ( many of which had simply updated Ptolemy's work, adding the effect of precession to the longitudes ) induced him to redetermine the positions of 992 fixed stars, to which he added 27 stars from Abd al-Rahman al-Sufi's catalogue Book of Fixed Stars from the year 964, which were too far south for observation from Samarkand.

Two astronomers particularly known for attempting to expand Ptolemy's catalogue were Johann Bayer ( 1572 – 1625 ) and Nicolas Louis de Lacaille ( 1713 – 1762 ).

Adhil was originally applied to the description of Ptolemy's 21st and 22nd of Andromeda in his star catalogue in Latin translated version of Almagest.

Ptolemy's problem is to forecast where, against the inverted bowl of night, some particular light will be found at future times.

In a sense, Einstein's theory is simpler than Newton's, and there is a corresponding sense in which Copernicus' theory is simpler than Ptolemy's.

Ptolemy's Ourchinion is further north than Ajaccio and does not have the same name.

The location of those Vandals is not stated, but there is a match with his contemporary Ptolemy's east German tribes.

Islay is Ptolemy's Epidion, the use of the " p " hinting at a Brythonic or Pictish tribal name, although the root is not Gaelic and of unknown origin.

The first mention of any tribes is in Ptolemy's description of European Sarmatia, where the main Prussian tribes are mentioned for the first time.

Although Abu Ma ' shar al-Balkhi | Abu Ma ' shar believed Ptolemy to be one of the Ptolemaic dynasty | Ptolemies who ruled Egypt after the conquest of Alexander the Great | Alexander the title ‘ King Ptolemy ’ is generally viewed as a mark of respect for Ptolemy's elevated standing in science.

There is little evidence on the subject of Ptolemy's ancestry, apart from what can be drawn from the details of his name ( see above ); however modern scholars refer to Abu Ma ’ shar ’ s account as erroneous, and it is no longer doubted that the astronomer who wrote the Almagest also wrote the Tetrabiblos as its astrological counterpart.

Ptolemy's other main work is his Geographia.

If they both used the Attic stadion of about 185 meters, then the older estimate is 1 / 6 too large, and Ptolemy's value is 1 / 6 too small, a difference explained as due to ancient scientists ' use of simple methods of measuring the earth, which were corrupted either high or low by a factor of 5 / 6, due to air's bending of horizontal light rays by 1 / 6 of the Earth's curvature.

Ptolemy's own title is unknown, but may have been the term found in some Greek manuscripts: Apotelesmatika, roughly meaning ' Astrological Outcomes ,' ' Effects ' or ‘ Prognostics ’.

Ptolemy's astrological outlook was quite practical: he thought that astrology was like medicine, that is conjectural, because of the many variable factors to be taken into account: the race, country, and upbringing of a person affects an individual's personality as much if not more than the positions of the Sun, Moon, and planets at the precise moment of their birth, so Ptolemy saw astrology as something to be used in life but in no way relied on entirely.

( This is the only complete English translation of Ptolemy's most famous work.

The year is stated as the ninth year of Ptolemy V's reign ( equated with 197 / 196 BC ), and it is confirmed by naming four priests who officiated in that same year: Aëtus son of Aëtus was priest of the divine cults of Alexander the Great and the five Ptolemies down to Ptolemy V himself ; his three colleagues, named in turn in the inscription, led the worship of Berenice Euergetis ( wife of Ptolemy III ), Arsinoe Philadelpha ( wife and sister of Ptolemy II ) and Arsinoe Philopator, mother of Ptolemy V. However, a second date is also given in the Greek and hieroglyphic texts, corresponding to, the official anniversary of Ptolemy's coronation.

Ptolemy's Geographia, written in the 2nd century, is sometimes considered to contain the first mentioning of the Saxons.

The construction of the zodiac is described in Ptolemy's Almagest ( 2nd century AD ).

That such deficiencies existed within Ptolemy's theory was not discovered de novo by Copernicus.

Ptolemy's view of Germans in the region indicates that the tribal structure had lost its grip in the Black Forest region and was replaced by a canton structure.

Reconstruction of Ptolemy | Ptolemy's map ( 2nd century AD ) of Aria ( satrapy ) | Aria ( Herāt ) and neighbouring states by the 15th century German people | German cartographer Nicolaus Germanus

1561 map of West Africa by Girolamo Ruscelli, from Italian translation of Ptolemy's Atlas “ La Geograpfia Di Claudio Tolomeo Alessandrino, Nouvamente Tradatta Di Greco in Italiano ”.

( not the Canary Islands, as long accepted ) as suggested by the location of the six dots labelled the " FORTUNATA " islands near the left extreme of the blue sea of Ptolemy's map here reproduced.

The maps in surviving manuscripts of Ptolemy's Geographia, however, date only from about 1300, after the text was rediscovered by Maximus Planudes.

In the 15th century Ptolemy's Geographia began to be printed with engraved maps ; the earliest printed edition with engraved maps was produced in Bologna in 1477, followed quickly by a Roman edition in 1478 ( Campbell, 1987 ).

( Ptolemy's own latitude was in error by 14 '.

* Ptolemy's Canon – a dated list of kings used by ancient astronomers.

* Ptolemy's theorem – mathematical theorem described by Ptolemaeus

* Ptolemy's world map – map of the ancient world as described by Ptolemaeus.

( The most recent edition of the Greek text of Ptolemy's astrological work, based on earlier editions by F. Boll and E.

* Ptolemy's Almagest, Translated and annotated by G. J. Toomer.

Two hundred years after the construction of Ptolemy's canal, Cleopatra seems to have had no west-east waterway passage, because the Pelusiac branch of the Nile River, which had fed Ptolemy's west-east canal, had by that time dwindled, being choked with silt.

Ptolemy's Tócharoi are often associated by modern scholars with the Yuezhi of Chinese historical accounts, who founded the Kushan empire.

In the third phase of the former Portuguese nautical cartography, characterized by the abandonment of the influence of Ptolemy's representation of the East and more accuracy in the representation of lands and continents, stands out Fernão Vaz Dourado ( Goa ~ 1520-~ 1580 ), whose work has extraordinary quality and beauty, giving him a reputation as one of the best cartographers of the time.

Ptolemy's maps, which became well known in Europe during the Renaissance, did not actually depict such a continent, but they did show an Africa which had no southern oceanic boundary ( and which therefore might extend all the way to the South Pole ), and also raised the possibility that the Indian Ocean was entirely enclosed by land.

* 1150s – Gerard of Cremona translates Ptolemy's Almagest from Arabic into Latin, eventually leading to its adoption by the Catholic Church as an approved text.

* The late Egyptian King Ptolemy IV's clique of favourites, led by Sosibius, Ptolemy's chief minister, keeps Ptolemy's death a secret, fearing retribution from the new king Ptolemy V's mother, Queen Arsinoe III.

* The Ptolemaic model of planetary motion: Based on the geometrical model of Eudoxus of Cnidus, Ptolemy's Almagest, demonstrated that calculations could compute the exact positions of the Sun, Moon, stars, and planets in the future and in the past, and showed how these computational models were derived from astronomical observations.

Purbach is also noted for his great attempt to reconcile the opposing theories of the universe, the so-called homocentric spheres of Eudoxus of Cnidus and Aristotle, with Ptolemy's epicyclic trains.