We have the planets, meteors showers and moon phases to look out for in December and a look at the deep sky objects in the constellations, Taurus & Gemini.

In the news we have Comet ISON at perihelion, a guide to comets, the Indian Mars Orbiter Mission and NASA's MAVEN both setting sail for Mars and a bizarre asteroid that thinks it's a comet. In the 5MC, Paul explains the mysterious and awe-inspiring majesty of a familiar object in the night sky – The Orion Nebula. Perfect to listen to as you observe it!

We open up our Christmas competition to win a year's subscription to Astronomy Now magazine and the European Southern Observatory's 2014 calendar.

We have two interviews this month – Dr Gareth Williams, who officially calculated Comet ISON's trajectory, tells us all about the comet; and Dr Gerhard Schwehm, ESA Project Scientist on the Giotto and Rosetta comet-chasing spacecraft missions.

Finally, we answer listeners' questions about the evidence for ancient alien visitors and the visibility of merging inactive black holes.