Astronomy Picture of the Day . Double Cluster in Perseus . ... 6.12.2007 . ... Some 7,000 light-years away, this pair of open or galactic star clusters is an easy binocular target and is visible to the unaided eye from dark sky areas. ... In addition to being physically close together, the clusters' ages based on their individual stars are similar - evidence that both clusters were likely a product of the same star-forming region. ... 2007 2008 . ... Publications with keywords: galactic cluster . ...