The Pleiades, (also known as Messier 45 ор the Seven Sisters), are an open star cluster located in the constellation of Taurus. Containing middle-aged, hot B-type stars, it is among the nearest star clusters to Earth and is the cluster most obvious to the naked eye in the night sky. The cluster is dominated by hot blue and extremely luminous stars that have formed within the last 100 million years. Dust that forms a faint reflection nebulosity around the brightest stars is an unrelated dust cloud in the interstellar medium, through which the star light is passing. The estimations are that the cluster will survive for about another 250 million years, after which it will disperse due to gravitational interactions with its galactic neighborhood. In 1966 Sidney van den Bergh has catalogued four reflection nebulae and has put them in his VdB Catalogue. Although these nebulae are part of the same interstellar cloud, he gave them four different catalogue numbers: VdB 20 (Magakian 51, Ced 19d or Electra Nebula), VdB 21 (NGC 1432, LBN 771, Ced 19f, Magakian 52 or Maia Nebula), VdB 22 (NGC 1435, Magakian 53, Ced 19j, GC 768, Merope Nebula or Tempel's Nebula ) and VdB 23 (Magakian 54 or Ced 19l). Please check the annotated mouseover image.