NGC 6859 is a bright open star cluster located in the constellation of Cygnus. It was discovered by the astronomer William Herschel in 1788. The cluster is approximately 3,600 light-years away from Earth and contains several hundred stars, many of which are young and hot. The stars in NGC 6859 are loosely bound by gravity, making the cluster relatively diffuse compared to other types of star clusters. It spans about 20 light-years across and is thought to be around 100 million years old, providing valuable insights into stellar evolution and the dynamics of star formation.