supernova remnant called the Cygnus Loop. determination method: SHA-1 described at URL: https://noirlab.edu/public/images/noao1209a URL: https://noirlab...
supernova remnant called the Cygnus Loop. determination method: SHA-1 described at URL: https://noirlab.edu/public/images/noao1209a URL: https://noirlab...