NGC 669 is a bright open star cluster located in the constellation of Cassiopeia. It was discovered by the astronomer William Herschel in 1788. This cluster is approximately 2,500 light-years away from Earth and contains several young, hot stars that are still in the process of forming. The cluster spans about 20 light-years across and is estimated to be around 100 million years old. NGC 669 is often studied for its stellar population and dynamics, providing insights into the formation and evolution of star clusters in our galaxy, the Milky Way.