Re: Triangulation at sea

From: Joerg Baumgartner <>
Date: Mon, 02 Jul 2001 23:58:08 +0000

>Jerome Blondel:
>>I didn't know about "the dread Tin Compasses". Surely a rare item!
>>Well, I guess the good chart isn't quite so easy to get too (especially
>>when you need to know the distance between, say, Nolos and Jrustela...)

Alex Ferguson
>True -- but if this triangulation technique were readily possible,
>making such charts would become both more easier and more accurate.

I note that the triangulation becomes somewhat less reliable if you are anywhere where the direction of the tin compass and the Red Moon are collinear. You need to work in the apparent height of the Red Moon, or there will be no triangulation at all. The reliability of the apparent height is a different matter, though. I'd feel much happier if I had a mountain like the Vent, which is known to be of an apparent height which remains constant. IMO the Vent ought to be useful about half the way to the Threestep Isles under conditions of normal haze (air resisting sight, yes).

Although height measurings on a ship rocking on the waves could be a tedious and highly unreliable thing to do, probably requiring a preparative spell which has the navigator swaying in a way to counter that movement.

(And I did not need to mention the flat world horizon anomaly...)

>>Also, "triangulation" and tin compasses would probably mostly be a Malkioni
>>(and maybe Kethaelan) thing, provided that the sailors don't go stricken
>>with fear when the captain takes measures of the Red Moon (don't the Red
>>Vadeli come from there?).

>Indeed, there's something rather reductionistically Malkioni about the
>whole method.

And, being west (or east) of the line Glamour-Magasta's Pool helps remaining with a two-dimensional problem. Kethaela is slightly east of that line, but then for all practical purposes, you can be south of Kethaela, too far south of Kethaela (Threestep Isles) or way too far south (Magasta's Pool). Maslo on the Pamaltelan coast has pretty much the same situation (Loral)...

But then I'd rather use the the place of sunrise or sunset for the absolute direction (which keeps the problem on the surface of a flat world). Luckily, with Theya and Rausa, it is possible to get an exact bearing on both gates, but I guess that the deviation from the straight line in between is as prone to mistakes as the triangulation to determine the distance between RW Earth and Sun based on the measurement of the angle of the sun some 800 miles north of Luxor on the day the sun would be directly overhead in Luxor, performed by some Alexandrian Greek chappy I could look up. He got the angle slightly wrong, and was off by two orders of magnitude IIRC.

This is from an excellent - German language - schoolbook "Mathematics of the Ancients", which gives all kind of mathematical problems e.g. the Pythagoreans were concerned with. A very Brithini pastime... If the world of nodes and higher essences can be perceived and controlled this way, a necessary ability for wizards, too. Arithmantics, or what?

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