Month: November 2022

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Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Reviewing Gundel

Having reviewed Vogt’s work, Grasshoff now turns to dissecting Gundel’s. As a reminder, Gundel discovered a $15^{th}$ century set of hermetic writings that contained a list of stars that was dated to the time of Hipparchus, potentially making it the first direct evidence of a Hipparchan star catalog.

But what Gundel’s analysis lacked is any exploration of how this related to  whether or not Ptolemy stole Hipparchus’ data. In this post, we’ll explore Grasshoff’s analysis of that topic. However, before doing so, Grasshoff works to ensure that we have the best possible understanding of the hermetic catalog before comparing the hermetic catalog to Ptolemy’s. Continue reading “Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Reviewing Gundel”

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Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Refining the Catalog

Over the past several posts, I’ve used the excellent history of the scholarly discussion surrounding the star catalog in the Almagest as given in Gerd Grasshoff’s History of Ptolemy’s Star Catalogue. At this point, we’ve caught up to the time the book itself was published. However, we’re not even half way through the book. The remainder of the text is Grasshoff reviewing the previous authors and offering a more comprehensive and in-depth analysis than done previously.

But before getting into that, Grasshoff attempts to ensure that we really understand the Ptolemaic catalog in its own right. For Grasshoff, this requires “a meticulous edition of the text and a correct identification of the ancient positional description with the stars known by their modern names,” as well as “the accurate position of the star at the historical epoch.” Continue reading “Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Refining the Catalog”

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Scholarly History of Commentary on Ptolemy’s Star Catalog: Newton (1977)

In the past few posts, we’ve demonstrated a rapidly forming consensus that Ptolemy’s star catalog was largely an original work. However, there were some holdouts. In $1977$ R. R. Newton published the book The Crime of Claudius Ptolemy1. In this work, Newton generally agrees with Lalande and Delambre – That Ptolemy’s “observations” are not true observations, but merely the result of theoretical calculations, extending this argument well beyond the star catalog, which Newton frequently describes as “fabricated”.

As a forewarning, this book raised a great deal of popular media attention as the alleged scheming of scientists is always a popular topic, but scientists reviewing the book have generally panned it as using flawed methodology, as we’ll see. Continue reading “Scholarly History of Commentary on Ptolemy’s Star Catalog: Newton (1977)”