First to Use the Sun to Establish Latitude

Since Portuguese navigators were so daring, it follows that they were the first to cross the equator (around 1471). Thus, they were also the first to realize that dead reckoning, the method by which all sailors used to navigate (using the North Star as a point of reference) was impossible after crossing the equator because “the North Star dipped below the horizon and disappeared entirely from view.”

The one celestial body that did not disappear after crossing the equator was the sun. After a very painstaking series of experiments and trial and error (and years, frankly; many, many years), they found a way to map the path of the Sun across the sky. They found a way to “determine latitude by the noontime altitude of the sun.” (Do NOT expect self to summarize all the calculations here!).

Portuguese ships were the first to reach the tip of Africa (in 1488). A decade later, the Portuguese had found the route to India.

Meanwhile, Spain looked like an absolute laggard, since all they had were the Spice Islands!

Later, Spain had the Philippines, which were actually in the Portuguese half of the world, as determined by the Treaty of Tordesillas. But maybe Spain exercised squatter’s rights: the Philippines remained a Spanish colony for 333 years.

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