NGC_6866 is an open star cluster located in the constellation Cygnus. It is approximately 3,800 light-years away from Earth and contains several bright stars that are relatively young, with ages estimated around 100 million years. The cluster is best observed with binoculars or small telescopes. Discovered by the astronomer William Herschel in 1784, NGC 6866 is notable for its loose structure and the presence of a few red giants among its members. The cluster is often studied for insights into stellar evolution and the dynamics of star formation in open clusters.