NGC 6866 is an open star cluster located in the constellation Cygnus. It is approximately 3,600 light-years away from Earth and contains around 50 stars, with its brightest member being of magnitude 9.5. The cluster is estimated to be about 100 million years old. Discovered by William Herschel in 1784, NGC 6866 is notable for its relatively loose structure and the presence of several blue stars, which indicate ongoing stellar evolution. Observations of this cluster can provide insights into the formation and development of star clusters in our galaxy, the Milky Way.