The Hercules Cluster (ACO 2151) is a rich galaxy cluster in the constellation Hercules, lying about 492 million light-years away, and reaches its annual culmination at astronomical midnight and is best observed late May.
The Hercules Cluster (ACO 2151) is a rich galaxy cluster in the constellation Hercules, lying about 492 million light-years away, and reaches its annual culmination at astronomical midnight and is best observed late May.