Ptolemy (about 85-165 AD) (original) (raw)

Claudius Ptolemaeus Pelusiniensis (Ptolemy) lived in Alexandria, Egypt approximately 85-165 AD or 87-150 AD, and worked there as philosopher, astronomer (and astrologer), mathemetician and geographer. He was of Greek origin. He created a number of monumental and epochal works, above all the_Mathematical Syntaxis_ ("Megale Syntaxas tes Astronomias," Great Syntaxas of Astronomy), which became the foundation of more than a millennium's astronomy, and is better known as Almagest(Ptolemy, ca. 130 AD). This work bound astronomical thinking in the western as well as the arabic world to geocentrism, but also gave positions of the "fixed" stars, and 48 constellations still used today. Other publications include his Geography, an early work of cartography and geography, and the astrological work Tetrabiblos.

Within Almagest, he lists seven nebulous objects, 3 of which are asterisms, but 4 are real deepsky objects; these are all open clusters. Two of them, Praesepe (M44) and the Double Cluster in h and _Chi_in Perseus, have been taken from Hipparchus, but the other two are new: the Coma Berenices Star Cluster (Mel 111)and "A Nebula behind the Sting of Scorpius", actually open star clusterM7 (now sometimes called Ptolemy's Cluster).

Ptolemy's work was widely and longly used by the educated community. In particular, his Almagest was used (and verified) by many consecutive observers, notably Al Sufi (903-986 AD) andUlugh Begh (1394-1449).Bigourdan (1892) has compiled a list including the positions of the nebulous objects presumably observed by Ptolemy and successors, see this list sorted by observer.

Nebulous objects mentioned in Ptolemy's Almagest:

No. Description Identification

175 In the right knee [of Cygnus] and 'nubisimilis' Omega1, Omega2 Cyg [cloud-like] 191 At the tip of the right hand [of Perseus] and h and Chi Per nebulous [or misty] 449 Center of the cloud-shaped convolutions in the Praesepe (M44) breast [of Cancer], called Praesepe 494 Most northerly part of the convolutions which are 15 Com and Mel 111 called Coma Berenices, between the borders of Leo and Ursa Major 567 Following the sting of Scorpius and nebulous M7 577 In the eye [of Sagittarius]; it is nebulous and Nu1, Nu2 Sgr double 734 Nebulosity in Orion's Head Lambda, Phi1, Phi2 Ori

Notes:

• Numbers are those in Bailly (1843), here taken from Kenneth Glyn Jones (1968)
• No. 567 was identified by Bigourdan as open cluster M7 (NGC 6475), a view is now generally accepted. Previously, Peter and Knobel have identified it with the star Gamma Telescopii (now G Sco) together with 8th-mag globular NGC 6441. The latter view is now rejected because of that globular's faintness.

Honors and such:

• Ptolemy's Cluster (Messier 7)
• Asteroid (4001) Ptolemaeus
• Moon Crater Ptolemaeus
• Mars Crater Ptolemaeus Links:
• Ptolemy biographical stuff from the Ptolemy's Supper Club
• Ptolemy biography from the MacTutor History of Mathematics archive, School of Mathematics and Statistics, University of St. Andrews, Scotland
• Ptolemy biography, Sun Education page, High Altitude Observatory
• Ptolemäus images, NGC/IC observers page
• Asteroid 4001 Ptolemaeus (1949 PV) (NEO/JPL) References:
• Ptolemy, ca. 130 AD. Megale Syntaxas tes Astronomias (Almagest).
  Ptolemy's Almagest was available online at the MAA.
  The edition Almagestum (1515) is available online at the University of Vienna.
  A translation of Ptolemy's catalog of stars is available online thanks to Brian Tung and the Sternberg Astronomical Institute of Moscow University.
• F. Baily, 1843. Description of the Catalogues of Ptolemy, Ulugh Begh, Halley and Hevelius. Mem. roy. astr. Soc., Vol. XIII.
• Guillaume Bigourdan, 1892. Observations of 1884. Observations de Nebuleuses et d'amas stellaires [Observations of Nebulae and Star Clusters]. Annales de l'Observatoire de Paris (Observations).Ptolemy's Catalog of "neboulous stars" extracted from this work.
• Kenneth Glyn Jones, 1968. The Search for the Nebulae -- I. Journal of the British Astronomical Association, Vol. 78, No. 4 (1968), p. 256-267. Section on Ptolemy: p. 261-263. Reprinted in: The Search for the Nebulae. Chalfont St. Giles, 1975.

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