How are stars and other objects in the sky named and located?
Hundreds of the brightest stars, those visible with the unaided eye, were given names in ancient times. These include Eltanin of Draco, the Dragon, and Vega in Lyra, the Lyre. Many of these stars have multiple names, having been observed by different cultures. Today stars are named by their coordinates on the celestial sphere. This is an imaginary sphere surrounding Earth. Earth’s north and south poles can be extended in space to this sphere, marking the north and south celestial poles, the poles around which the sphere spins. Polaris marks the intersection of the extended north pole and the sphere. Earth’s equator, extended into space, intersects the sphere at the celestial equator, dividing it into northern and southern hemispheres. All stars and objects in space, such as constellations, can be mapped relative to the poles and equator of the celestial sphere. Their position north or south of the celestial equator — essentially their latitude — is called “declination.” Their position
