Sh 2-4, also known as Sharpless 2-4, is a bright emission nebula located in the constellation of Cassiopeia. It is part of a larger complex of nebulae and is approximately 2,000 light-years away from Earth. The nebula is known for its striking colors, which are produced by ionized gases, primarily hydrogen. This nebula is often studied by astronomers to understand the processes of star formation and the dynamics of interstellar matter. Sh 2-4 is associated with a young star cluster, which contributes to the illumination of the surrounding gas and dust, making it a fascinating object for both amateur and professional astronomers.