Pleiades open star cluster, 1888. These bright young stars are surrounded by interstellar gas and dust. This gas and dust is a part of a reflection nebula surrounding the stars. The Pleiades (the Seven Sisters) is an open star cluster of over 1000 stars, of which around 14 are visible to the naked eye. It is around 440 light years from Earth, in the constellation of Taurus. Observed by Welsh astronomer Isaac Roberts from his observatory at his home in Crowborough, Sussex, UK, on 8 December 1888.