This time the team have taken on an astonishing challenge - to capture one of the top highlights of the solar system - the mysterious and elusive northern lights. But will the lights reveal themselves? Liz Bonnin reports live from within the Arctic Circle, joining aurora researchers in northern Norway, who will help her unravel the secrets of this eerie spectacle.

Brian Cox and Dara O Briain host the second night of their three-day stargazing extravaganza from Jodrell Bank Observatory, where they are joined by two generations of astronauts. Walt Cunningham was one of the first ever crew to fly an Apollo spacecraft into orbit, while Commander Chris Hadfield recently returned from months aboard the International Space Station.

Brian Cox and Dara O Briain raise the stakes in the final night of their astronomy extravaganza, and reveal the results of their viewers' challenge to find undiscovered galaxies at the edge of space.