Sh2-191 is a bright emission nebula located in the constellation of Cassiopeia. It is part of a larger complex of star-forming regions and is known for its striking appearance, which is primarily due to the ionization of gas by nearby hot stars. The nebula is approximately 8,000 light-years away from Earth and spans several light-years in diameter. This nebula is often studied by astronomers to understand the processes of star formation and the dynamics of interstellar gas. Sh2-191 is also associated with the LBN 762 dark nebula, which obscures some of the light from the stars behind it, creating a beautiful contrast in the night sky.