The next manuscript I’ve reviewed is the Paris graecus $2391$, a copy of which can be found here. Continue reading “The Almagest Manuscripts – Paris 2391”
The Almagest Manuscripts – Paris 2390
The third manuscript I’ve reviewed is the Paris $2390$. A copy of it can be found here. Details below the fold. Continue reading “The Almagest Manuscripts – Paris 2390”
The Almagest Manuscripts – Paris 2389
In an effort to make sure the various manuscripts of the star catalog that I have copied into my spreadsheet are accurate, I have attempted to located images of the original copies when possible to review each value even when transcriptions are available. Each manuscript has its own unique eccentricities so, as I go through them, I’d like to dedicate a post to discussing the various things I notice.
To start with, I’ll discuss the Paris $2389$ manuscript, beginning with an overview of how to read the Greek. As a note, I’m not getting into translating the descriptions which is far beyond my skill level. Rather I’ll just discuss the coordinates and magnitudes since the catalogs generally keep the same order1.
New Class Announcement – Ptolemy’s Star Catalog: A Stolen Masterwork? 2/15/23
On Wednesday February 15, 2023, I will be teaching my new class on the history of Ptolemy’s Star Catalog at the weekly meeting for the Barony of Three Rivers. It follows the discussion of whether or not the figures were stolen from Hipparchus. If you’ve been reading this blog, you’ve already seen the vast majority of the material, but this talk gives a summary of it.
Almagest Book VII – VIII: The Star Catalog
Before diving into the star catalog itself, there’s quite a bit I want to say about it. But if you don’t want to wait, here’s a link to the Google Sheet where I’ve transcribed it. More information is below the fold. Continue reading “Almagest Book VII – VIII: The Star Catalog”
A Note on the Manuscripts and Translations of the Almagest
Before I present the star catalog, I want to briefly discuss some of the extant manuscripts. This is because I’ve decided to try to maintain relevant footnotes from Toomer’s translation that discuss variations in coordinates between manuscripts. Continue reading “A Note on the Manuscripts and Translations of the Almagest”
2022 in Review
And that’s a wrap on 2022. Let’s look back on this year and remember what I got done! Continue reading “2022 in Review”
Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Fractions of a Degree in Latitude
So far, all of the tests that Grasshoff has reviewed to try to determine whether or not Ptolemy used a Hipparchan star catalog have proven inconclusive. In the last post, we showed that the solar theory was quite obviously in use in constructing the star catalog. This provides a reasonable explanation for the mean error being $\approx 1º$ as well as why the distribution of errors could have matched Hipparchus’ even without Ptolemy having used his data2. But just because it provides a reasonable explanation of how Ptolemy could have gotten similar incorrect results doesn’t mean that he did. Thus, Grasshoff needs another way to try to distinguish between these two historical interpretations.
Grasshoff now turns to the frequency of the fractions of degrees which he describes as a “powerful criterion to decided between suggested historical interpretations.” Continue reading “Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Fractions of a Degree in Latitude”
Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Errors in the Solar Theory
So far in Grasshoff’s analysis, he’s come to the conclusion that the distribution of errors (as well as some of the specific ones) point to Ptolemy having used Hipparchus’ data. The only possibility to rescue Ptolemy as an observer is if there is some sort of underlying bias in both of their observations that led to a similar set of errors.
The primary suspect for this would be errors in the solar theory because Ptolemy’s model was essentially the same as that of Hipparchus’3. So, at long last, Grasshoff is ready to explore the errors in the solar theory. Continue reading “Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Errors in the Solar Theory”
Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Structures in the Catalog
In the last post, we followed along as Grasshoff explored the distribution of errors within Ptolemy catalog as compared to those of the reconstructed Hipparchan one. He demonstrated that the errors are highly correlated indicating that Ptolemy likely did use Hipparchan data, unless there was a systematic error common to both.
To build on that concept, Grasshoff begins exploring structures in the catalog by mapping the position of the stars in Ptolemy’s catalog as compared to the true positions as calculated by modern astronomy for the year $137$ CE4. Mapping things in this manner allows for several patterns to become apparent.