The best of astronomy this month: Catch a few meteors from the Geminids meteor shower on 13th-14th December.
By Dhara Patel, Astronomy Education Officer
(Details given are for London and may vary for other parts of the UK).
Top 3 things to see this month:
- Throughout the month - Look for the Pleiades in the east and Mars in the south in the early evening.
- 13-14th Dec - Scan the sky to spot a few meteors from the Geminids meteor shower around midnight.
- 27-30th Dec - Watch the Moon pass by the bright stars Regulus and Spica.
Look Up! Podcast
As well as taking you through what to see in the night sky each month, Royal Observatory Greenwich astronomers pick their favourite astro news story. For December, they're chatting about Mars rovers - the likely end of one (Opportunity), the landing sight chosen for another (Mars 2020) and the landing of a third (InSight) along with a news story about where all the Sun's siblings have gone and the likely discovery of one of them! Have a listen below then vote for your favourite news story on our Twitter poll during the first week of the month.
Our podcast is available on iTunes too - search Look Up! and rate us if you enjoyed listening.
As the sun sets and the skies begin to darken, the constellation of Taurus the Bull will rise over the eastern horizon remaining visible throughout the night as it moves from east to west. The bright red star Aldebaran denotes the star at the eye of the bull and makes it easier to spot this star pattern. Shining bright in Taurus is the Pleiades or Seven Sisters. Easily seen with the naked eye (even with some light pollution), this open cluster of hot, blue, young stars is actually a collection of hundreds of stars rather than just the seven visible with the naked eye and this multitude of stars can be made out with a pair of binoculars or preferably a telescope. As Taurus comes into sight, the constellation of Orion the Hunter follows closely behind – a wonderful winter star pattern to also feast your eyes and optics on!
Mars still sits proudly in the southern sky in the early evening – a great naked eye target to look for as you wait for the skies above to darken. Its red colour should become notable as your eyes become dark adapted but use even a moderate telescope to make out some of the darker and lighter patches on this rusty-red coloured planet. Venus has been too close to the Sun to be visible recently but throughout December is will continue to move towards its greatest western elongation (which it will reach in early January). This means it will become easier to spot and much brighter – look towards the east in the early hours before the sun rises. Typically being the last bright point of light visible before the Sun rises (apart from the Moon); Venus is often known as the morning star.
On the morning of 3rd December, Venus will sit beneath the waning crescent moon and with the aid of the blue-white star Spica; the three will form a triangle shape above the south-eastern horizon.
We are graced with one of the best annual meteor showers this month – the Geminids. Peaking on the night of 13th / early morning of 14th December – wait until after midnight and scan the sky with your eyes to spot a few ‘shooting stars’. This meteor shower is one of a few that shows good activity before midnight too. Although the meteors will appear to radiate out from the constellation of Gemini in the south, they can be seen all over the sky and with a possible hourly rate of over 100 meteors (in optimal viewing conditions) it’s well worth a look. In the height of winter it’s important to wrap up warm. Head out to dark skies if possible and take along a deck chair if possible – it’s a lot of looking up! The Geminids are actually thought to be the product of the debris left behind from an asteroid rather than a comet. The denser rocky material from asteroid Phaethon produces slower meteors which appear to last longer. Another meteor shower (the Ursids) peaks later in the month on December 21-22 but with a maximum hourly rate of 5-10 and with the full moon present - conditions aren’t particularly favourable.
The comet 46P/Wirtanen will be visible in our skies this month, with best visibility in the UK on December 16th. Our astronomers will be looking to spot the Comet through the Annie Maunder Astrographic Telescope at the Royal Observatory. You can watch the Live broadcast on Facebook to hear experts talking about the comet and to see our astronomers tracking the comet's progress through the sky.
However, the 21st of December is still an important date in the astronomical calendar – it marks this year’s winter solstice; for those of us in the UK it denotes the start of astronomical winter or sometimes midwinter. On this day the northern hemisphere has its maximum tilt away from the Sun and we experience the shortest hours of daylight and the longest hours of darkness. Appropriately the December full moon is known as the cold moon and it will appear the following evening – rising in the east around sunset and remaining visible throughout the night until just before the sun rises the next day.
Towards the end of the month look out for the Moon passing by a few bright stars. If you can wait until after midnight, look towards the south-east and return at the same time over the next few nights. On 26th or 27th December, catch the Moon beside Regulus - the brightest star in the constellation of Leo the Lion. On the 29th the Moon will be in its last quarter phase. The terminator (boundary between the light and dark sides of the Moon) will be clearly visible now. This is where the craters on the Moon appear to stand out so grab your binoculars or telescope to spot a few! By the 30th, the Moon will be near Spica – marking the bale of wheat held by Virgo the Maiden.
The Moon's phases this month
- 7 Dec - new moon (7:20am)
- 15 Dec - first quarter moon (11:49am)
- 22 Dec - full moon (5:49pm)
- 29 Dec - last quarter moon (9:34am)
- When looking at faint objects such as stars, nebulae, the Milky Way and other galaxies it is important to allow your eyes to adapt to the dark - so that you can achieve better 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're using a star app on your phone then switch on the red night vision mode.
- Need a stargazing telescope or binoculars? Check out our range of high quality observing equipment recommended by Royal Observatory astronomers:
Share your astronomy pictures
Congratulations to Phill Froggett for his stunning image of the night sky. He shared his image on our astrophotography Facebook page and we chose it for December's banner image.
If you want to be in with a chance to showcase your astrophotography skills on the banner of next month's night sky blog, share your photos via our Royal Observatory Astrophotography Facebook group
You can also connect with us on Twitter: @ROGAstronomers
Hubble Vision - gallery exhibition
Come and see some of the most spectacular images taken by the Hubble Space Telescope in our free exhibition at the Royal Observatory Greenwich.
The exhibition is open daily until 12 May 2019.
See more of the night sky
Come on an amazing tour of this month's night sky in our Sky Tonight planetarium with a festive twist during December. The show is delivered live by a Royal Observatory Greenwich astronomer.
Central image: © Phill Froggett
Resources for teachers and students
The Royal Observatory learning team have also created:
- Free animated videos that answer the biggest questions in astronomy and free resources to go alongside them.
- A whole host of podcasts featuring interviews with real space scientists, astronauts and active researchers working in UK Universities.