Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

A Survey of the AlmagestThe Fixed Stars

A Survey of the Almagest: The Fixed Stars [In Books VII and VIII of the Almagest Ptolemy interrupts the development of the planetary theories in order to deal with a number of problems connected with the fixed stars. The reason for this is explained in the prologue to this second part of the Almagest [VII, 1; Hei 2, 2], where Ptolemy tells his friend or protector Syrus (see page 26) that the further development of planetary theory presupposes a chapter on the so-called fixed stars. The reason is that while the solar theory was founded upon simple observations of solstitial and equinoctial times, and the lunar theory upon eclipses, the theories of the remaining five planets are, to a great extent, founded upon exact determinations of planetary longitudes derived from the distance of the planet in question from a fixed star, measured with the astrolabon (see page 183). Thus a position of Mercury is referred to Aldebaran (α Tauri) [IX, 7; Hei 2, 262] or to Regulus (a Leonis) [ibid.; Hei 2, 263] just as a longitude of Venus is found relative to that of Antares (a Scorpii) [X, 3; Hei 2, 303].] http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png

A Survey of the AlmagestThe Fixed Stars

Loading next page...
 
/lp/springer-journals/a-survey-of-the-almagest-the-fixed-stars-BE6b5L29gc

References (0)

References for this paper are not available at this time. We will be adding them shortly, thank you for your patience.

Publisher
Springer New York
Copyright
© Springer Science+Business Media, LLC 2011
ISBN
978-0-387-84825-9
Pages
236 –260
DOI
10.1007/978-0-387-84826-6_8
Publisher site
See Chapter on Publisher Site

Abstract

[In Books VII and VIII of the Almagest Ptolemy interrupts the development of the planetary theories in order to deal with a number of problems connected with the fixed stars. The reason for this is explained in the prologue to this second part of the Almagest [VII, 1; Hei 2, 2], where Ptolemy tells his friend or protector Syrus (see page 26) that the further development of planetary theory presupposes a chapter on the so-called fixed stars. The reason is that while the solar theory was founded upon simple observations of solstitial and equinoctial times, and the lunar theory upon eclipses, the theories of the remaining five planets are, to a great extent, founded upon exact determinations of planetary longitudes derived from the distance of the planet in question from a fixed star, measured with the astrolabon (see page 183). Thus a position of Mercury is referred to Aldebaran (α Tauri) [IX, 7; Hei 2, 262] or to Regulus (a Leonis) [ibid.; Hei 2, 263] just as a longitude of Venus is found relative to that of Antares (a Scorpii) [X, 3; Hei 2, 303].]

Published: Oct 14, 2010

Keywords: Proper Motion; Reference Star; Precessional Motion; Vernal Equinox; Lunar Theory

There are no references for this article.