M 1 (or NGC 1952), better known as the Crab Nebula, is a planetary nebula in the constellation of Taurus, 6,500 light years away.It is the remnant of a supernova that became visible to the naked eye on July 4, 1054.
M 57 or NGC 6720 is a planetary nebula in the constellation of Lyra and it is what remains of a supernova explosion.At its center there is a white dwarf which is what remains of the supernova core.