Pease 1 is a planetary nebula located within the globular cluster M15 33,600 light years away in the constellation Pegasus. It was the first planetary nebula known to exist within a globular cluster when it was discovered in 1928[2] (for Francis G. Pease), and just four more have been found (in other clusters) since.[1] At magnitude 15.5, it requires telescopes with an aperture of at least 300-millimetre (12 in) to be detected.[3]