Sky maps have been assembled over the millennia by astronomers since the beginning of history. Ancient Chinese, Babylonian, Egyptian, Polynesian, and Native American civilizations all had carefully drawn maps of the stars, with their positions relative to one another carefully recorded. Over time, astronomers developed a coordinate system across the sky: each celestial object’s location can be precisely described by its right ascension, or east-west position, and its declination, or north-south position.