Stargazing in December: Mars shines more brilliantly than any of the stars

Grab a telescope, if you can, to home in on our planetary neighbour any night this month, says Nigel Henbest

Red planet Mars is the ‘star of the month’ (Madhav fallusion/CC BY-SA 4.0)

It’s bright, it’s red, and it’s high in the sky as we approach Christmas. No, I’m not talking about Rudolph’s nose as he leads Santa’s other reindeer. It’s the planet Mars, swinging by the Earth on 1 December, when it’s only 81 million kilometres away – the closest it’s been in more than two years.

Throughout the month, Mars shines more brilliantly than any of the stars, with its unmistakeable reddish glow. And we are in for a rare treat in the early morning of 8 December, when the full moon moves right in front of the Red Planet.

It’s surprisingly rare to observe the moon occult a planet: I’ve only seen it happen on a handful of occasions in my lifetime as an astronomer. And this occultation is highly unusual, in that it’s not just Mars, the moon and the Earth that are lined up, but the sun as well. The moon is opposite to the sun in our sky – the moment of full moon – at 4.08am on 8 December; and Mars is at opposition to the sun just 16 minutes later, at 4.24 am. (That’s a week after its closest approach, because Mars’s orbit is not circular but elliptical.)