Scholarlink

<p>In <i>Almagest</i> XIII, Ptolemy explains his latitude theories for the superior and inferior planets. There he provides, among other things, the values for the inclinations of the planets eccentres and epicycles. The methods and observations Ptolemy uses to calculate the values of these inclinations are highly problematic and are one of the main reasons for the predictive difficulties of the models. This is because they yield a final value for the inclinations of the eccentre and epicycle which are, in many cases, grossly incorrect. The latitude models for the superior planets in the <i>Planetary Hypotheses</i> signify a definitive improvement in the sense that they provide very accurate inclinations for both the eccentre and the epicycle. The main purpose of the paper is to present a simple and plausible explanation of how Ptolemy could have arrived at the accurate values he provides in the <i>Planetary Hypotheses</i>. As we will show, the method we propose is consistent with Ptolemy’s general methodology when facing similar problems. Also, and crucially, we will show that they relate to the work he had done in the <i>Almagest</i> on the latitude tables. Finally, we will show that in the years he was probably starting to work in his post-<i>Almagest</i> modifications, he had at his disposal potential observations which were very well suited to our method.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

On Ptolemy’s improvement of the parameters of the latitude models for the superior planets

  • 期刊论文

  • 发表日期：

    2026年3月9日

查看全文
  • Gonzalo L. Recio,
  • Christián C. Carman

摘要

In Almagest XIII, Ptolemy explains his latitude theories for the superior and inferior planets. There he provides, among other things, the values for the inclinations of the planets eccentres and epicycles. The methods and observations Ptolemy uses to calculate the values of these inclinations are highly problematic and are one of the main reasons for the predictive difficulties of the models. This is because they yield a final value for the inclinations of the eccentre and epicycle which are, in many cases, grossly incorrect. The latitude models for the superior planets in the Planetary Hypotheses signify a definitive improvement in the sense that they provide very accurate inclinations for both the eccentre and the epicycle. The main purpose of the paper is to present a simple and plausible explanation of how Ptolemy could have arrived at the accurate values he provides in the Planetary Hypotheses. As we will show, the method we propose is consistent with Ptolemy’s general methodology when facing similar problems. Also, and crucially, we will show that they relate to the work he had done in the Almagest on the latitude tables. Finally, we will show that in the years he was probably starting to work in his post-Almagest modifications, he had at his disposal potential observations which were very well suited to our method.