December 20
Globular Cluster M15
Observed in 1998
These stars belong to the globular cluster M15. Nestled among them is an astronomical oddity. The pinkish object to the upper left of the cluster's core is a gas cloud surrounding a dying star. Known as Kuestner 648, this was the first planetary nebula found in a globular cluster.
Image credit: NASA, ESA, Hubble Space Telescope