Constellations

This document discusses key concepts in astronomy including constellations, celestial coordinates, the celestial sphere, and the zodiac. It defines constellations as areas of the sky containing groups of stars and other objects. Modern astronomy divides the sky into 88 constellations. Celestial coordinates like declination and right ascension are used to specify the positions of stars and constellations on the celestial sphere. The zodiac represents an annual cycle of twelve constellations along the ecliptic.