Saturday, Sep 7, 2024

CTB 1 (Abell 85) is a supernova remnant (leftovers from an exploding star), similar to the famous Veil Nebula in Cygnus but much fainter. Its size in the sky is similar to the size of a full moon and it is approximately circular. Note, however, that its outer shell has ruptured between the 7 and 8 o'clock position. Originally this was thought to be a planetary nebula (which is why it appears as Abell 85 in his catalogue of planetaries) but in 1971 it was determined that it is actually a supernova remnant.