Simeis 147 supernova remnant, optical image. The glowing filaments of gas and dust are the remains of a supernova explosion, or explosive death of a large star. The gas ejected from the explosion expands outwards, colliding with interstellar material at high speed. The shock of the impact ionises the gases, causing them to glow. The star is thought to have exploded around 30,000 years ago. Simeis 147 lies 3000 light years away in the constellation Taurus. At lower right (red dot) is the nebula SH2-242 (LBN 826). This image, taken in 2020, was captured in H-alpha and visible light (RGB) from the Alqueva Dark Sky Reserve in Portugal.