Star-studded cluster

NGC 6717 is a globular cluster that lies over 20,000 light years away from Earth in the constellation of Sagittarius. Globular clusters are – as the name suggests – clusters of stars that are held together so tightly by gravity they form an almost-spherical shape. This particular glittering scene was captured by the Hubble Space Telescope. A variety of cosmic interlopers can be seen in this image, with bright foreground stars that are closer to Earth surrounded by criss-cross diffraction spikes. These spikes are caused by starlight interacting with the support structures of Hubble’s secondary mirror.