A real Hubble Space Telescope color image of the core of the globular star cluster Omega Centauri is used to construct a Hertzsprung-Russell diagram of the stellar populations in the cluster. When stars are sorted by brightness and color, they can be used to create a graph that astronomers use to trace cluster evolution.
Credit: NASA, ESA, and J. Anderson, R. van der Marel, G. Bacon, and M. Estacion (STScI)
Additional information is available on HubbleSite:
http://hubblesite.org/newscenter/archive/releases/2010/28