NGC 6520 is an open star cluster located in the constellation Sagittarius. It is approximately 5,000 light-years away from Earth and contains around 30 stars. The cluster is relatively young, with an estimated age of about 10 million years. One of the most notable features of NGC 6520 is its proximity to the bright nebula Barnard 86, which is a dark cloud of dust that obscures the light from stars behind it. This contrast creates a striking visual effect, making NGC 6520 an interesting target for amateur astronomers and astrophotographers.