Barnard's Loop, also known as Sh2 264, is an emission nebula around 518 to 1,434 light-years away. It is believed to have originated from a supernova explosion about 2 million years ago. As seen from Earth, it is centered on and covers the entire constellation of Orion
Barnard's Loop, with the Horsehead and Orion Nebulae on its lower-right center
Constellation diagrams enabled, showing how Barnard's Loop covers the entire constellation of Orion