LOS ANGELES - Skywatchers are in for a holiday treat, as Jupiter and Saturn are set to cross paths in the night sky.The phenomenon is nicknamed the "Christmas star" and the vibrant planetary conjunction will be easily visible to the naked eye as a "double planet.""Jupiter and Saturn are the two largest planets in our solar system, and Jupiter is moving faster than Saturn, so every 20 years, Jupiter overtakes Saturn," Henry Throop, an astronomer with NASA, told FOX TV Stations. (NASA)According to NASA, the celestial event will culminate on the evening of Dec.