Planetary conjunction, optical image. Seen just after sunset are the planets Mars (highest spot at upper left), Saturn (lower right of Mars) and Mercury (lowest dot closest to centre). At lower left of Saturn is an open star cluster, called Praesepe (also named Beehive or Crib), which lies in the centre of the constellation Cancer. At far right is the star Castor and directly left is its bright sibling Pollux, both of which form the heads of the twins in the constellation Gemini. This conjunction took place at 21:33 on 23rd June 2006 and was viewed from the Observatory at La Palma in the Canary Islands.