RSGC1-F01 is a red supergiant star located approximately 22,000 light-years away in the constellation Scutum. With an estimated radius of 1,450 to 1,530 solar radii, it is one of the largest stars known. The supergiant is member of the massive young star cluster RSGC1. Discovered in 2006, the cluster and its members are invisible to the unaided eye and cannot be seen in optical telescopes.