Almagest

Up to the present, the results of these investigations are far from being conclusive.

Ptolemy, one thirty AD, wrote the Syntaxis, or Almagest, which includes a cyclopedia of astronomy, containing a summary of knowledge at that date.

We have no evidence beyond his own statement that he was a practical observer.

He theorized on the planetary motions and held that the Earth is fixed in the center of the universe.

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In this way they obtained a knowledge of the great works of Ptolemy, both in astronomy, which they regarded as the more important and therefore the greatest Almagest, and also in geography, though one can easily understand the great modifications which the strange names of Ptolemy must have undergone in being transcribed, first into Syriac and then into Arabic.

We shall see later on some of the results of the Arabic Ptolemy.

The conquests of the Arabs affected the knowledge of geography in a twofold way, by bringing about the Crusades and by renewing the acquaintance of the West with the east of Asia.

So because we're saying Greek stuff, I'll mention that there's only one Greek book, and then there's three or four books from Sanskrit.

So the Greek thing is Ptolemy's Almagest.

This is the astrological book about, you know, all sorts of stuff.

And that is mentioned next to an Indian book, a Sanskrit book that we don't really know about.

Kosha is a word for a book.

And so okay, something about time.

It's right next to Almagest, which we know is astrological.

Maybe this is some astrological book.

So I, I mentioned before that the origins of astrology were very practical, and then today not necessarily so much, but we owe that to the Greeks.

So the royal predictions of Babylonian astrology became personal horoscopes around 200 BCE in ancient Greece, and then a couple hundred years later in 150 CE, Ptolemy comes along, publishes the Almagest, the, like, official list of the 48 Greek constellations that we still use today.

He called them katasterismoi, which meant, uh, placed by the gods.

They were messages or lessons placed by the gods, and that's why the Greek constellations all have stories associated with them because those stories were meant to teach us things and th- th- you know, they were important because the gods gave us those lessons by immortalizing different figures or different moments in the sky as constellations.

It maybe has, like, a few exoplanets that we've discovered in it, but it doesn't look anything like a microscope.

The shape of the asterism and the constellation border are both bad.

Next we have Corvus, which is included in the Almagest.

It's also seen in the Babylonian charts.

The scientific movement of the later Alexandrian period found its consummation in the geographer, astronomer, and mathematician Claudius Ptolemy, not to be confused with the rulers of that name.

He was most active, 127 to 151 AD, and is best known by his work, the Syntaxis, which summarized what was known in astronomy at that time.

Ptolemy drew up a catalog of 1,080 stars based on earlier works of Hipparchus.

He followed that astronomer in teaching that the earth is the center of the movement of the heavenly bodies, and this geocentric system of the heavens became known as the Ptolemaic system of astronomy.

To Hipparchus and Ptolemy, we owe also the beginnings of the science of trigonometry.

The Syntaxis set forth his method for drawing up a table of chords.

For example, the side of a hexagon inscribed in a circle is equal to the radius and is the chord of sixty degrees, or of the sixth part of a circle.

The radius is divided into sixty equal parts, and these again divided and subdivided sexagesimally.

And because the Greeks saw them as moving objects in contrast to the unchanging heavens, they called them wanderers.

When Latin scholars picked up the term, it became planet or planeta, preserving that wanderer meaning, but also beginning to appear in medieval astronomy texts like the Arabic translations of Ptolemy's Almagest.

By the Middle Ages, French writers had adopted the word as planete, and by the thirteenth century, we see it crop up in English glossaries alongside Latin terminology.

In English, the first real use shows up around the late medieval period.

He was, as you said, living in Alexandria, where he had access to all kinds of materials at the library and museum in Alexandria.

And he started pulling together all of this ancient storehouse of knowledge and into the book that he wrote that folks later in the medieval period would call the Almagest.

It was a name given to that book by Islamic scholars that essentially meant the greatest, that this is the greatest book ever written about astronomy.

And it was that book, the Almagest, and also another work of Ptolemy's called the Tetrabiblos, these four books about astrology.

They came to define that medieval worldview for the Islamic world and then also for Christian Europe, giving them not only this structured heavens of these nested spheres, but with all of the planets, including Mars, you know, moving in perfect circles, but also this knowledge about the significance of that, of what it meant when Mars or any other planet was in a different part of the sky or behaving in certain ways.

And yeah, there were things that Ptolemy couldn't really explain very well, like that change in appearance of Mars or the retrograde motion of Mars.

It's claimed the 12 zodiacal constellations originated in Babylon, but this is the mainstream idea, and it remains within the textbooks of history, and I'm no longer satisfied with most of the mainstream stuff.

As for the oldest and most valuable constellations we have, Ptolemy and the Almagest is where we got them, and we've covered this to some degree.

The detailed compilation of the oldest constellations dates back to Claudius Ptolemy, who in the second century BC, that is, presented a catalog of 1,022 stars.

These were grouped into 48 constellations within his work called the Almagest.

The importance of the Almagest should be noted, and the reason for our coverage for the Almagest Nuovo not too long ago, and that was a very telling episode when we broke it down, It should be further noted that the time of the book's inception, Tycho Brahe, I'm talking about the 1500s book, 16th century, Tycho Brahe was king of the sky clock.

And we point that out in the episode.

But what we got was not Tycho's work.

But the rabbis didn't get that from Revelation.

They got it from a Greek astronomer named Ptolemy, who wrote a book called the Almagest.

So in any event, and Ptolemy got it, who wrote the Almagest, he got this from Babylonian astronomical observations going back about a thousand years before him.

I wanted to mention that out of all of the questions that we get, most of the questions that we get are not about how do I keep this holiday, but it's exactly when the community sat in.

You guys are asking those questions now too.

Anyway, so that's real simple.

That's just such a simple explanation.

And by the way, how do I know that they didn't know how to calculate the visibility of the new moon? Even the conjunction, like I said, it was Ptolemy's Almagest is the first time that a reliable calculation is given even for the average time of one lunar cycle to the next and that's based on a thousand years of babylonian astronomy so that's that's that's a thousand years basically after jonathan is talking to david roughly so i mean that's just an it's what we call an anachronism it's something that doesn't fit the time period to say they use calculations Somebody asked, so if we see new moon at sunset, next day is day one and then Yom Kippur is day 10 or Yom Kippur is day nine at sunset.

So you don't get generational change in economics.

And therefore, in that sense, it's like the pre-Galilean sciences where rather than saying, what does experiment tell us and how do we have to change our theory? They say, what does the great book say? Now, in the case of astronomy, it was the Almagest by Ptolemy and Aristotle's Nicomachean Ethics.

That's what you go and read to see whether the Earth moved or not.

Same thing for economics.