101 Must-See Cosmic Objects: The Hercules galaxy cluster

For observers who own or have access to large telescopes and a dark viewing site, one of the most impressive sights in the sky is the Hercules galaxy cluster. Also known as Abell 2151, this group of galaxies takes the term deep sky to a whole new level. It lies at the astounding distance of 500 million light-years.

If your scope has a go-to drive, its database may not contain Abell galaxy clusters. Instead, just target this cluster’s brightest member, elliptical galaxy NGC 6047. Without