Skygazers will be treated to a bigger and brighter moon this weekend as the final 'supermoon' of the year moves closer to Earth.
December's full moon - traditionally known as the Cold Moon - will appear 14% bigger and 30% brighter than usual on Sunday.
The exact moment of full moon - when the moon sits opposite the sun in the sky - will be 3.47pm, with moonrise about 45 minutes later.
Tom Kerss, an astronomer at Royal Observatory Greenwich, said: "This year's Cold Moon is closer to us than the average full moon this year; close enough to qualify as a supermoon, according to the widely accepted definition.
"The moon will reach its highest point above the horizon at midnight local time. This is when, weather permitting, it will appear at its clearest and brightest."
Why does the moon look bigger and brighter?
The moon has a slightly elliptical orbit - it does not move round the Earth in a perfect circle.
At some points it is about 5% closer to Earth than average, known as perigee, and at others it is 5% further away, known as apogee.
The full moon will be 222,761 miles from Earth, closer than its average 238,900 miles.
Mr Kerss said: "During moonrise and moonset, you might think the moon looks unusually large, but this is an illusion created in the mind when it appears close to the horizon.
"In fact, the change in the moon's apparent size throughout its orbit is imperceptible to the unaided eye.
"Nevertheless, the 'moon illusion' can be a dramatic effect, and with the moon rising so early, there will be ample opportunities to see its apparently huge face juxtaposed with the eastern skyline.
Is it safe to look at a supermoon?
Mr Kerss advises: "It's perfectly safe to look directly at the full moon, even with a telescope or binoculars.
"You can see many of the moon's larger features, although at full moon its surface looks rather flat, since we don't see any shadows cast across it until its night side begins to creep into view.
"However it is possible to see the dark maria (seas) in stark contrast to the brilliant highlights of the full moon if you allow your eyes to adjust and pick out these ancient volcanic flood plains, once filled with lava."
How can I get good pictures of the supermoon?
1. Go to an an area without street lights, to avoid light pollution.
2. Try to get a building or some other land-based landmark in the frame.
3. Use people to bring your shot to life - can you get someone to 'hold' the supermoon in their hand?
4. If you're using a DSLR camera, use faster shutter speeds.
5. If your budget doesn't extend that far, work out how to adjust the exposure on your smartphone, and focus on the moon, not the other things in the picture.
What if I miss it? When's the next one?
The next one will be in January 2018. In fact there'll be two - on the 2nd and the 30th of the month.
* Don't forget to send your supermoon pictures to us - and we'll use the best online and maybe in the paper too.