Sh2-157 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 primarily due to the ionization of hydrogen gas by nearby hot stars. The nebula is approximately 1,000 light-years away from Earth and spans about 30 light-years across. This nebula is often studied by astronomers to understand the processes of star formation and the dynamics of interstellar gas. Sh2-157 is also associated with the Sh2 catalog, which lists various bright nebulae in the night sky. Its beauty and complexity make it a popular target for both amateur and professional astrophotographers.