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Topic
chevron_rightAntiquity Studies

Language
en

ISBN (print)
978-88-7543-440-3

ISBN (ebook)
978-88-6969-165-2

ISSN Filologia e letteratura
chevron_right2610-8836

e-ISSN Filologia e letteratura
chevron_right2610-9352

Date of publication
01 Sep 2017

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Antichistica

Astronomy and Geography
Some Unexplored Connections in Ptolemy

Klaus Geus
Freie Universität, Berlin, Deutschland
klaus.geus@fu-berlin.de

Irina Tupikova
Lohrmann Observatory, Technische Universität Dresden, Deutschland
irina.tupikova@googlemail.com

DOI 10.14277/6969-165-2/ANT-13-4

Submitted 13 Jan 2017
Accepted 31 Mar 2017

Abstract

The authors discuss the so-called ‘zenith star method’, first mentioned in Ptolemy’s Geography (ca. AD 150), from an astronomical and historical perspective. They reach the conclusion that the exact representation in some texts, i.e. that the distance between the two points of culmination is 1°, does not in fact concern a pair of stars culminating at the zenith but only one star which is measured at an angle of 1Æ from the zenith. This peculiar condition points to a historical measurement carried out by an unknown Greek astronomer: it makes use of the fact that the bright star Pollux (β Geminorum) culminated at Alexandria with an angle distance of 1° from the zenith or (which is equivalent) culminated at the zenith over a place 1° south of Alexandria (ca. 110 km). Although a scholium to Ptolemy’s Geography claims this, the unknown author of the experiment is in all probability not Hipparchus of Nicaea.

Keywords
Hipparchus. Ptolemy. Circumference of the earth. Zenith star method.


Creative Commons License This work is licensed under a Creative Commons Attribution 4.0 International License 

Table of contents
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Campo DC Valore

dc.contributor.author

Geus Klaus

dc.contributor.author

Tupikova Irina

dc.title

Astronomy and Geography

dc.type

Book Chapter

dc.language.iso

en

dc.description.abstract

The authors discuss the so-called ‘zenith star method’, first mentioned in Ptolemy’s Geography (ca. AD 150), from an astronomical and historical perspective. They reach the conclusion that the exact representation in some texts, i.e. that the distance between the two points of culmination is 1°, does not in fact concern a pair of stars culminating at the zenith but only one star which is measured at an angle of 1Æ from the zenith. This peculiar condition points to a historical measurement carried out by an unknown Greek astronomer: it makes use of the fact that the bright star Pollux (β Geminorum) culminated at Alexandria with an angle distance of 1° from the zenith or (which is equivalent) culminated at the zenith over a place 1° south of Alexandria (ca. 110 km). Although a scholium to Ptolemy’s Geography claims this, the unknown author of the experiment is in all probability not Hipparchus of Nicaea.

dc.relation.ispartof

Antichistica

dc.relation.ispartof

Filologia e letteratura

dc.publisher

Edizioni Ca’ Foscari - Digital Publishing

dc.date.issued

2017-09-01

dc.dateAccepted

2017-01-13

dc.dateSubmitted

2017-03-31

dc.identifier.uri

http://doi.org/10.14277/6969-165-2/ANT-13-4

dc.identifier.issn

2610-8828

dc.identifier.eissn

2610-9344

dc.identifier.isbn

978-88-7543-440-3

dc.identifier.eisbn

978-88-6969-165-2

dc.rights

Creative Commons 4.0 Attribution alone

dc.rights.uri

http://creativecommons.org/licenses/by/4.0/

item.fulltext

with fulltext

item.grantfulltext

open

dc.subject

Hipparchus

dc.subject

Ptolemy

dc.subject

 Circumference of the earth

dc.subject

 Zenith star method

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