Sharpless 2-4 is a bright emission nebula located in the constellation of Cassiopeia. It is part of a larger region of star formation 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 associated with the open cluster NGC 281, which contains young, hot stars that contribute to the ionization of the surrounding gas. Sharpless 2-4 is often studied by astronomers to understand the processes of star formation and the dynamics of interstellar matter.