Tracing the history of medieval astronomy
Finally, in the discussion of Ptolemy’s star catalog, we’ll be moving beyond Grasshoff1.
In this post, we’ll explore a new technique, first considered in the late $1980$’s to use high proper-motion stars to attempt to determine the epoch of the star catalog. Continue reading “Scholarly History of Commentary on Ptolemy’s Star Catalog: Proper Motion Analysis”
Previously, we discussed Vogt’s attempt to reconstruct the Hipparchan catalog by reverse calculating its coordinates from Hipparchus’ Commentary on Aratus. This Commentary was Hipparchus’ response to a poem by Aratus entitled the Phaenomena. Grasshoff ultimately took issue with Vogt’s methods, finding them insufficiently explained given the number of assumptions required to perform the transformation, to put too much stock in. Although not overtly stated, the fact that no one else has attempted to reproduce Vogt’s methods with better explanations, including Grasshoff himself, implies that the uncertainty surrounding such assumptions are considered sufficiently prohibitive that it is not worth attempting to refine Vogt’s methods.
However, Grasshoff isn’t finished with the Aratus Commentary just yet. While the issues with the dates and longitudes may make the Aratus Commentary too messy to use to reverse calculate Hipparchus’ catalog from, Grasshoff instead proposes going the other way around – using Ptolemy’s catalog to calculate same rising/culminating/setting descriptions given in the Aratus Commentary. These can then be compared to those in the Aratus Commentary without needing to worry about recovering Hipparchus’ catalog. Continue reading “Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Ptolemy’s Phaenomena”
In the last post, we explored a few potential explanations for the distributions of the increment for latitude. In this post, we’ll explore the various explanations for the distribution in longitude.
What Grasshoff is really doing in this section is exploring various scenarios and asking which one best gives the reason for the distribution of increments in longitude. So let’s take a look at the different scenarios. Continue reading “Scholarly History of Commentary on Ptolemy’s Star Catalog: Grasshoff (1990) – Fractions of a Degree in Longitude”
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 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”
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 order2.
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.
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”
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”
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”