Having determined a correction for the equant for the first opposition, we’ll now repeat the procedure for the second. The diagram to do so is identical to the previous one, but is flipped over the line of apsides. Continue reading “Almagest Book X: Correction for Equant – Second Opposition”
Data: April 8, 2024 Total Solar Eclipse
This past Monday, I spent the day in Mountain View, AR with one of the members of my Barony and their family to catch the eclipse. Continue reading “Data: April 8, 2024 Total Solar Eclipse”
Almagest Book X: Correction for Equant – First Opposition
Having gotten our preliminary estimate for the eccentricity and position of apogee
let us investigate the differences which can be derived from them in the ecliptic arcs which we week to determine at each of the oppositions [in turn].
In this post, we’ll cover Ptolemy’s method for the first opposition. Continue reading “Almagest Book X: Correction for Equant – First Opposition”
Almagest Book X: Preliminary determination of Mars’ Apogee & Eccentricity – Part 2
In the last post, we began the process of determining Mars’ eccentricity and the position of apogee. The technique is fundamentally similar to the three eclipse method used for the moon, but the presence of the equant is throwing a wrench in things. Specifically, in that previous post we showed that an line extended through the observer from one of the observations did not have a length of $120^p$ which affirmed that the observer was still off center.
So in this post, we’ll use that information to determine how far off center so that we can complete the task we set about. Continue reading “Almagest Book X: Preliminary determination of Mars’ Apogee & Eccentricity – Part 2”
Almagest Book X: Preliminary determination of Mars’ Apogee & Eccentricity – Part 1
In the last Almagest post, Ptolemy explained that for the models of the superior planets, we’ll be needing to use oppositions. So with that explained, we’ll begin by working to develop the model for Mars by looking at its eccentricity and apogee.
As with many previous posts, we’ll start with a series of observations. He tells us that these observations were taken using the “astrolabe”. However, we need to recall that what Ptolemy called the astrolabe, we would think of as an armillary sphere. Thus, the methodology here was to align the equatorial ring with the celestial equator, and ensure that, when the planet was sighted, its position was $180º$ from the calculated position for the mean sun.
So here are the observations: Continue reading “Almagest Book X: Preliminary determination of Mars’ Apogee & Eccentricity – Part 1”
Gulf Wars 2024 Schedule
I’ve gotten confirmation on all my classes for Gulf Wars. A list is below the fold. Continue reading “Gulf Wars 2024 Schedule”
The Almagest Manuscripts – Vatican Graecus 1594
I have finished my review of the Vatican Graecus $1594$ manuscript and it is available in my Google Doc. If you’d like to view the original manuscript, it can be found here, starting on $155r$1.
Discussion of this catalog below the fold. Continue reading “The Almagest Manuscripts – Vatican Graecus 1594”
2023 in Review
Welcome to 2024 everyone!
$2023$ is now behind us, so I want to take a moment to review my progress for this year. Continue reading “2023 in Review”
Almagest Book X: Preliminary Comments Regarding the Models for Superior Planets
Having completed the preliminary models for the inferior planets, Mercury and Venus, Ptolemy now turns his attention towards the superior ones: Mars, Jupiter, and Saturn. Continue reading “Almagest Book X: Preliminary Comments Regarding the Models for Superior Planets”
Almagest Book X: Venus’ Epoch Position
Now that we’ve worked out the mean speed of Venus about the epicycle, we can now determine where it was on the epoch date. Continue reading “Almagest Book X: Venus’ Epoch Position”