How Does a Sextant Work?

A sextant is like a super-smart ruler you use to measure angles between things in the sky, just like when you line up your toys on the floor and count how far apart they are.

Imagine you're playing with two mirrors. One mirror is attached to the sextant, and the other is inside your eye. When you look through the sextant at something in the sky, like the sun or a star, it bounces off the mirror on the sextant and comes back to your eye, just like when you see yourself in two mirrors at once.

You can move the mirror on the sextant up and down. When the image of the object you're looking at lines up with another object, like the horizon, that means the angle is perfect! You then measure how much you moved the mirror, which tells you the angle between the two objects.

It's like when you try to line up your fingers to see how many fit on a ruler, except instead of fingers and a ruler, it’s mirrors and angles in the sky. Cool, right?