The Crescent Nebula, also known as NGC 6888, is a bright emission nebula located in the constellation Cygnus. It is approximately 5,000 light-years away from Earth and spans about 25 light-years across. The nebula is formed from the gas and dust expelled by a massive star, known as HD 192163, which has reached the end of its life cycle. This nebula is characterized by its crescent shape, which is created by the interaction of stellar winds from the central star with the surrounding material. The intense radiation from the star ionizes the gas, causing it to glow in various colors, primarily red and blue. The Crescent Nebula is a popular target for amateur astronomers and astrophotographers.