Aristyllus

Aristyllus (Greek: Ἀρίστυλλος; fl. c. 261 BC) was a Greek astronomer, presumably of the school of Timocharis (c. 300 BC). He was among the earliest meridian-astronomy observers. Six of his stellar declinations are preserved at Almajest 7.3. All are exactly correct within his over-cautious rounding to 1/4 degree. See discussion (and lessons) at DIO 7.1 ‡1 p. 13 (2007).

Aristyllus was long mis-dated to c. 300 BC (which made his data look among the poorest of the ancients); but when his correct date was found by least-squares (Isis 73:259-265 [1982] p. 263), it was realized that his star declinations' accuracy was unexcelled in antiquity. His data suggest that he worked in Alexandria: see DIO 4.1 ‡3 Table 3 p. 45 (2004).

A lunar crater, Aristillus, aptly near the Moon's meridian and at a lunar latitude roughly equal to the terrestrial latitude of Alexandria, is named after him.
Sources

Thomas Hockey's Biographical Encyclopedia of Astronomers provides the following information about him:[1][2]

"Aristyllus was an early astronomer in the school of Alexandria. Little is known about him. He made astronomical observations during the first half of the third century BCE, and was probably a pupil of Timocharis."

"Aristyllus and Timocharis are usually considered to have compiled the first true catalog of the fixed stars, in which stars are identified by numerical measurements of their positions."

William Smith's Dictionary of Greek and Roman Biography and Mythology provides the following information about him:[3]

"Aristyllus, a Greek astronomer, who appears to have lived about B.C. 233. He wrote a work on the fixed stars (τηρήσις ἀπλανῶν), which was used by Hipparchus and Ptolemy, and he is undoubtedly one of the two persons of this name who wrote commentaries on Aratus."
References

"Aristyllus - Springer". springerreference.com. Retrieved 2014-12-10.
Hockey, T.; Bracher, K.; Bolt, M.; Trimble, V.; Palmeri, J.A.; Jarrell, R.; Marché, J.D.; Ragep, F.J. (2007). Biographical Encyclopedia of Astronomers. Springer. p. 62. ISBN 9780387304007. Retrieved 2014-12-10.

"A Dictionary of Greek and Roman biography and mythology, Abaeus, Ari'stophon, Aristyllus". perseus.tufts.edu. Retrieved 2014-12-10.

External links
"Greek astronomy". www-history.mcs.st-and.ac.uk. Retrieved 2014-12-10.

vte

Ancient Greek astronomy
Astronomers

Aglaonice Agrippa Anaximander Andronicus Apollonius Aratus Aristarchus Aristyllus Attalus Autolycus Bion Callippus Cleomedes Cleostratus Conon Eratosthenes Euctemon Eudoxus Geminus Heraclides Hicetas Hipparchus Hippocrates of Chios Hypsicles Menelaus Meton Oenopides Philip of Opus Philolaus Posidonius Ptolemy Pytheas Seleucus Sosigenes of Alexandria Sosigenes the Peripatetic Strabo Thales Theodosius Theon of Alexandria Theon of Smyrna Timocharis

Works

Almagest (Ptolemy) On Sizes and Distances (Hipparchus) On the Sizes and Distances (Aristarchus) On the Heavens (Aristotle)

Instruments

Antikythera mechanism Armillary sphere Astrolabe Dioptra Equatorial ring Gnomon Mural instrument Triquetrum

Concepts

Callippic cycle Celestial spheres Circle of latitude Counter-Earth Deferent and epicycle Equant Geocentrism Heliocentrism Hipparchic cycle Metonic cycle Octaeteris Solstice Spherical Earth Sublunary sphere Zodiac

Influences

Babylonian astronomy Egyptian astronomy

Influenced

Medieval European science Indian astronomy Medieval Islamic astronomy

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