... Hurtling through a cosmic dust cloud a mere 400 light-years away, the lovely Pleiades or Seven Sisters star cluster is well-known for its striking blue reflection nebulae. ... M45: The Pleiades Star Cluster . ... Perhaps the most famous star cluster on the sky, the Pleiades can be seen without binoculars from even the depths of a light-polluted city. ... A system of stars numbering in the hundreds of thousands, it is one of the brightest globular star clusters in the northern sky. ...