Caldwell 86 is one of the nearest globular clusters to Earth. Its closeness, combined with Hubble’s sharp vision, allowed astronomers to measure the cluster’s parallax — or how much it appears to move in the sky as Earth travels from one side of the Sun to another.
Credits: NASA, ESA, and T. Brown and S. Casertano (STScI); Acknowledgment: J. Anderson (STScI)