You don’t need a fancy sextant to try this. Your own hand works as a rough angle measure. At arm’s length, your pinky finger covers about 1° of sky, your fist is about 10°, and your spread hand from thumb to pinky is about 20°. I once impressed my nephew by “measuring” a skyscraper’s height using his hand. The look on his face was priceless.
Now, for the sun. At local noon—when the sun is at its absolute highest point—you measure its angle above the horizon. This is trickier because the sun’s position changes with the seasons. But the old trick is: latitude = 90° - solar angle + a seasonal correction. It sounds mathy, but it’s just subtraction and a little lookup table.
Remember those shadow sticks you made as a kid? You can use one today. Stick a straight pole in the ground, mark the shortest shadow around noon, and measure the angle of that shadow. Congratulations, you just did the same math as a 15th-century explorer.
3 Ways to Determine Latitude and Longitude - wikiHow
