He didn't develop Celestial Navigation. And he wasn't even very good at it.
Lol, yes he did, perfecting techniques theorized by others and himself.
Columbus and Celestial Navigation
Columbus was from Genoa, one of the leading Mediterranean ports, and he must have learned his dead reckoning navigation from Genoese pilots. But he had spent time in Portugal, and was aware of all the new ideas in navigation, including celestial navigation. So on his first voyage he made at least five separate attempts to measure his latitude using celestial methods. Not one of these attempts was successful, in part because of bad luck, and in part because of Columbus's own ignorance of celestial techniques and tools....
The quadrant readings Columbus obtained on his first voyage are horrible by any standard. Some have suggested that Columbus mistook another star for Polaris, but that seems ridiculous: Columbus used the stars of Ursa Minor to tell time at night, so he was very familiar with that constellation. In 1983, James E. Kelley, Jr. provided the solution to the mystery: as mentioned above, many quadrants in maritime museums have tangent scales. If Columbus misread the scale, he might have recorded the tangent of his latitude (without the decimal point) instead of his actual latitude. If that were the case, Columbus's measurements would only be wrong by a couple of degrees or so, which is not bad considering the technology.
In any case, it is clear that at this point in his career Columbus was not familiar enough with celestial techniques and tools to use them successfully....
(Third Voyage)
Giving Columbus every benefit of the doubt, we may assume that he measured the altitude of Polaris on August 1, 1498, at the Boca del Sierpe (10 N, 62 W) at the beginning of nautical twilight -- the time when the Sun reaches 6 degrees below the horizon, and bright stars first become visible. This occurred at 2249 UT for that date and location. At that time, Polaris was already 8° 10' above the horizon, and rising -- compared to Columbus's report of less than 5 degrees.....
Not much of Columbus's own writing about the fourth voyage survives today. But we do know that while marooned on the north coast of Jamaica, he found his latitude to be 19°, which is within a degree of the correct number. This high accuracy could only have been achieved if Columbus had been using celestial techniques. It also suggests that even late in his life, Columbus continued to be fascinated with the latest navigational methods, and continued to learn.
Columbus demonstrated and perfected the theory of his own and others in his voyages.
Compare the way the Portugese sailed along the coast of Africa to how they sailed after Columbuses voyages.
And if you are giving Columbus credit for the crops he brought back to the Old World, are you blaming him for the devastating results of the Potato Famine?
Lol, he did not introduce the potato fungus, lolol
