For thousands of years, humans have used the stars to learn about the planet we live on. From star sightings, you can map the change of seasons, navigate the oceans, and even determine the
size of Earth.
Polaris, or the North Star, has occupied an important place in human history. The location of Polaris is not affected by Earth's rotation. At any given observation point, it always appears
at the same angle above the horizon. At Earth's North Pole, Polaris appears directly overhead. At the equator, it is just above the northern horizon. Polaris provides a standard from which
other locations can be measured. Such star sightings can be made using the astrolabe, an instrument used to measure the height of a star above the horizon.