One of the things coming up in the campaign I'm running is the bit in Ancient Magic about magical geography and the Hesperides. Although the text about how the magical coordinates work is clear enough, I'm a bit unsure about what is meant by the Origin Point. The text says that one can't reach the Origin Point, because no one's ever been there, except some Carthagan hero names Hanno.
First question then: Why can't one go there? It's far, yes, but it's a place. The next question is: where is it on modern maps? Am I correct in guessing that it's the point where the Equator meets the zero longitude, south from the Canary Islands?
I'm asking just so I can answer some of the questions that the players will want to ask themselves
Yes, it is where the Equator meets the Zero Meridian.
Hanno got closest: indeed he may have got there since he seems to have circumnavigated Africa in some versions of the story. It depends on your cosmology, but in some of the stuff that's been written for Ars, the Equator is a ring of impassable flame that destroys everything on either side of it for miles. You can't do an astrological observation there because it's the middle of a wall of impassable, unquenchanble flame, which makes it difficult to breathe, see the stars, have something to stand on, and so on.
Or it could just be Really Far Away, which is less of a hassle, sure.
In Art and Academe, it says (in the bit about Geography) that the Great Ocean seperates the north and south hemisphere of the world, and it's the source of all moisture. Does that mean that there are no land anywhere across the equator in the setting? Just trying to understand the meaning here.
I'm reasonably sure that that was from William of Conches, but I will check my sources tonight and post a correction if I'm wrong. He divides the land into four with an equatorial ocean and a meridonal ocean. We live on just one of those land-masses (so the whole of the O and T map - 'Africa' and 'Asia' included - exists in just a quarter of the earth). A&A suggests that the three sublunar Realms might physically exist on the other three: Infernal in the Antipodes - directly opposite our zone and beneath Jerusalem, a la Dante; Magic below us; and Faerie to the West.
Not really. In Mythic Europe, Africa was thought to be a lot smaller than the modern continent, ending somewhere around the Sahara desert. South of that was the Equatorial ocean, and a great ring of fire above it.
Unlike latitude, which has the equator as a natural starting position, there is no natural starting position for longitude. Therefore, a reference meridian had to be chosen. It was a popular practice to use a nation's capital as the starting point, but other significant locations were also used. While British cartographers had long used the Greenwich meridian in London, other references were used elsewhere, including: El Hierro, Rome, Copenhagen, Jerusalem, Saint Petersburg, Pisa, Paris, Philadelphia, and Washington. In 1884, the International Meridian Conference adopted the Greenwich meridian as the universal prime meridian or zero point of longitude. Source: wiki
Yes. They weren't very useful because you couldn't measure them very well, and there wasn't any sort of international agreement on where the zero should be.
A lot of Alexandrian-influenced geographers used the Canariy Islands as the zero meridian, because it was the westernmost known point, and so it wasn't necessary to use negative numbers to represent places to the west of your chosen meridian. That makes the maths easier.