Celestial contest: Geminids vs Supermoon


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We are about to experience a celestial contest between the very bright full Moon ‘Supermoon’ and the annual Geminids meteor shower. Royal Observatory astronomer Brendan explains all.

What is it?

Supermoon by Tom Kerss
Supermoon, by Royal Observatory astronomer Tom Kerss

A 'Supermoon' is a term used to describe the Moon when it’s closer than normal to the Earth. The Moon appears up to 14% bigger and 30% brighter than the furthest a full Moon can be.

The Geminids is a chance to see many ‘shooting stars’ in the sky as a result of the Earth ploughing through an asteroid’s debris trail. This is an annual event, but as it’s best seen under dark skies the bright full Moon will make viewing it a challenge!

When is it?

The full Moon is at its closest on 13 December at 11.23pm. The Geminids are best seen across the night of the 13th and early morning (pre-dawn) of the 14 December, although these meteors can be seen either side of these dates for at least a few days.

How do I watch it?

So long as there’s not too much cloud, the full Moon will be an unmistakable white orb in the sky. Seeing moonrise just after sunset or moonset just before sunrise will be an impressive sight as it will appear enormous compared to the surrounding landscape, due to an illusion.

The Geminids are best seen in the hours between midnight and dawn when your position on Earth is turning towards the debris trail mentioned earlier. However, with a bright Moon in the sky only the largest and brightest meteors called fireballs will be visible. To be in with the best chance, try to avert your vision from the Moon to give your eyes a chance to capture the fainter light from meteors.

This challenging scenario could lead to an exciting opportunity for any photographers. Set up your camera to take a good picture of the Moon and take as many snaps as you can, one after another. You might just be lucky enough to capture the Moon and a fireball in the same shot, which should look spectacular!

Get prepared for stargazing

When looking at faint objects such as the stars, nebulae, the Milky Way and other galaxies it is important to allow your eyes to adapt to the dark – so that you achieve night vision. Allow 15 minutes for your eyes to become sensitive in the dark and remember not to look at your mobile phone or any other bright device when stargazing. If you are using a star app on your phone switch on the red night vision mode.

Need a stargazing telescope or decent binoculars? Check out our range of high-quality observing equipment recommended by Royal Observatory astronomers:

See our range of observing equipment

Share your astronomy pictures

Don’t forget to share your pictures of the night sky with us on Twitter @ROGAstronomers or via Facebook. Come and see amazing astronomical images of the night sky in our free Insight Astronomy Photographer of the Year exhibition, now open at the Royal Observatory.

Visit the free Insight Astronomy Photographer of the Year exhibition

See more of the Christmas night sky

Come on a fantastic seasonal tour of the night sky in our Christmas Stars planetarium show, join one of our special evenings of live astronomy, or get the lowdown on life in space in our Royal Observatory Christmas Lecture.

See the Christmas Stars planetarium show

An Evening with the Stars - live stargazing