The night sky in the Northern Hemisphere for December 2017
2 months 3 weeks ago

The night sky in the Northern Hemisphere, December 2017
December is a fabulous month for star clusters, nebulae and meteor showers. It is also the darkest part of the year as the Winter Solstice falls on 21st December, where the Sun is at its most southerly declination (it is one of two angles which indicates a position on the celestial sphere). It also means the North Pole is tilted at the furthest point away from the Sun. The Full Moon falls on 3rd December and New Moon on 18th December.

On 13th - 14th December from the middle of the evening until dawn,  the Geminid Meteor shower  reaches a peak and promises to be a breath-taking pre-Christmas treat, as it is the most reliable and strongest meteor shower of the year. You will start to see ‘shooting stars’ (meteors) from this shower from 7th December. The Geminid shower was first observed in the mid-19th Century and more recently, was discovered in 1982 to be the cometary debris left by 3200 Phaethon.  At 75-120 meteors per hour, the best time to watch it is around midnight. The good news is that there will be no moon light to wash out the sky. A special feature of this shower is that the meteors can be colourful. Pull out your sun lounger, dress warmly and remember to allow around half an hour for your eyes to adapt to the dark.  Enjoy!

The planet Uranus
Jupiter rises from 5:30am from 1st December and climbs to at least 20 degrees above the horizon by dawn on 31st December.  Look out for Mars close by.
Uranus, a gas giant, is positioned in Pisces and requires a star map to find it. You may be able to find it using the map above. Try and locate it using binoculars at first; you might be able to see a greenish blob which would be as a result of its methane atmosphere.  At around 150 times magnification with a 3 inch telescope, the planet can be resolved to a blue-green disk.

Auriga constellation
There are some beautiful star clusters to study this month. Through binoculars, study the rich region of Auriga. You will see some fuzzy patches within the constellation which are open clusters M36, M37 and M38. Through 10x50 binoculars, they all appear within the field of view. Try to see how many stars you can resolve in each object – you should be able to see at least 9 stars in M38. The 'M' designation stands for Messier, named after French astronomer Charles Messier, who specialised in comet hunting. Through his 4 inch telescope he saw the same objects, night after night, that looked like comets but didn't have cometary motion. As a result of that frustration, he devised a catalogue of open clusters, globular clusters, galaxies and nebulae that could be avoided! These days, amateur astronomers use Charles Messier's catalogue of 110 objects as a reference for exploration!
Returning to Auriga: between two of these Messier targets is a great asterism. The Cheshire Cat Asterism can be seen between M38 and M36 and resembles a smiley face! Try and find it for yourself with your binoculars, or click this ‘spoiler’ link for its location.

Owl Cluster in Cassiopeia
The Owl Cluster (NGC 457) is a beautiful sight through telescopes. It can be seen through small telescopes with a 25mm eyepiece. It was first discovered by William Herschel in 1787 and is situated 7,900 light years from the Sun. Start with the eyes, one of which is brighter than the other, and then try to spot the Owl’s body and outstretched wings.

Eskimo Nebula in Gemini
Through a 6 inch telescope and from 50 times magnification, the Eskimo Nebula (NGC 2392) in Gemini appears to twinkle in and out of vision and can appear bluish in colour. With averted vision, the fuzzy outer halo with a brighter core can be resolved, which resembles a person’s head wearing a furry hood. This nebula magnifies well. Through larger telescopes, its colour is more accentuated and you may even be able to see the central core surrounded by a dark ring. NGC 2392 is a planetary nebula, which is formed during the process of a dying star which ejects its outer gaseous layers and forms beautiful nebulae. William Herschel discovered this object in 1787. It is believed to  2,900 light years away, although the precise distance is not known.

Flame Nebula in Orion

The Flame Nebula (NGC 2024) in Orion is another tricky target and needs quite dark skies to see it. This emission nebula, illuminated by Alnitak, is part of the Orion Molecular Cloud Complex, including the stunning Orion Nebula (M42) which was included in last month’s report. At around 1500 light years away, it is also home to several hundred very young stars, with its older members around the outskirts of the nebula. With an 8 inch telescope and a 25mm eyepiece, find the star Alnitak and nudge it very slightly to the left, keeping the bright star out of the field of view. When your eyes adapt, you should see a dark, rough, central pillar flanked by wisps of nebula.

With Christmas drawing near, the Elan Valley Dark Skies team would like to wish you happiness this holiday season and throughout the coming year - and most of all, clear skies!