Sh2-158 is a bright emission nebula located in the constellation of Cassiopeia. It is part of a larger region of star formation and is known for its striking colors, which are produced by ionized gases. The nebula is approximately 1,200 light-years away from Earth and spans about 30 light-years across. This nebula is associated with the open cluster NGC 281, which contains young, hot stars that contribute to the ionization of the surrounding gas. Sh2-158 is often studied by astronomers to understand the processes of star formation and the dynamics of interstellar matter.