The Night Sky in December 2006

Sunrise and Sunset Times for the UK

	Edinburgh Sunrise Sunset		Manchester Sunrise Sunset		London Sunrise Sunset
Dec 01	08:17	15:45	08:00	15:56	07:42	15:57
Dec 15	08:37	15:38	08:18	15:50	07:58	15:53
Dec 30	08:45	15:46	08:25	15:57	08:08	16:00

To find out today's sunrise and sunset times for where you are, click here

Phases of the Moon


New Moon Wednesday 20th	First quarter Wednesday 27th	Full Moon Tuesday 5th	Last quarter Tuesday 12th

Click HERE to see the phase of the Moon on each day of the month.

What's happening in the night sky?

Now that the darkest month of the year is upon us there is plenty of opportunity to explore the night sky from your back garden - weather permitting of course. Sunset times will get earlier until the winter solstice (more about that later) on the 22nd December, after which, the days will start to get longer again.

Maps of the current night sky can be seen by clicking HERE

December 4th - Moon passes through the Pleiades star cluster

During the early hours of the 4th December, the Moon will pass slowly through the Pleiades star cluster over the course of a few hours. The animation below runs in one hour steps from around 1.30am until 6.30am, so if you are up and about well before dawn, and brave enough to face the cold, you may want to observe this amazing and unusual spectacle.

Animation of the Moon passing through the
Pleiades star cluster on 4th December © Stellarium

The Pleiades star cluster is a young open cluster located 440 light-years away in the constellation of Taurus (see later). The cluster is more commonly known as the Seven Sisters because of the fact that on a dark night, naked-eye observers can usually see seven bright stars. In fact the Pleiades cluster contains many hundreds of stars, which becomes more evident if you look at it through a telescope or binoculars. The stars in the Pleiades are very young stars that are slowly drifting out of the gas and dust cloud in which they were born. Compared to our middle-aged Sun, these bright stars are mere babies who haven't learnt to walk yet.

December 22nd - Winter Solstice

The winter solstice, or mid-winters day, is the point during Earth's orbit around the Sun where those in the northern hemisphere see the shortest period of daylight. Solstice literally means the stopping or standing still of the Sun, and the stopping it refers to is the Sun reaching its lowest point above the horizon around mid-day. In summer (around June 21st) the summer solstice marks the longest day of the year and the Sun reaching its highest point above the horizon around mid-day.

Height of Sun at noon

These changes in daylength is all down to the tilt of the Earth in relation to the Sun, and without it we wouldn't have any seasons. Of course countries in the southern hemisphere, like Australia and South Africa, will be having their longest day of the year on the 22nd because they are tilted toward the Sun in December, whereas we are tilted away. If this is a bit confusing, try going to the spinning Earth section to see that the length of day is different depending on the time of year and on where you are in the world.

What are the planets up to?

Click HERE and start the Electric Orrery to see where all the planets are today in relation to each other.

Mercury - spends the whole month as a morning object. At the beginning of December it will rise in the east-southeast just under two hours before the Sun. This reduces during the month as Mercury slowly positions itself to move behind the Sun early in the New Year.

Venus - is currently an evening object and will remain so right through until August 2007. In the first few days it will set in the south-west around 20 minutes after the Sun. This will increase to about an hour by January.

Mars - continues to move away from the Sun (as viewed from Earth) and will remain a morning object. During the month it will appear over the southeast to east-southeast horizon between 60 and 90 minutes before the Sun, although this will increase over the next few months as we slowly catch Mars up on our inside orbit. Try using the electric orrery to see how Mars becomes more observable over the coming year.

Jupiter - reached conjunction (far side of the Sun) on the 21st November and is now re-appearing as a morning object. By the end of December, Jupiter will rise in the south-southeast a couple of hours before the Sun makes an appearance. Although we are still unable to observe the largest planet with the Liverpool Telescope, by the spring we should be getting decent images again.

Saturn - remains the only planet we can get reasonable images of. At the start of the month, it will rise in the east-northeast just before 10pm and reaches high above the southern horizon by 5.30am. Both these times move forward two hours by month's end as we continue to catch Saturn up. If you fancy bagging an image of a planet, why not try your luck using Go Observing.

Constellation of the month

Each month, a new constellation is highlighted for you to identify in the night sky.

This month, we are going to look for the constellation of Taurus, the Bull, which can be found above the eastern horizon during the evening. The constellation can be located using the bright red-giant star, Aldebaran, which is one of the brightest stars in the night sky and marks the bull's eye of Taurus. The horns of the Taurian "bull" stretch off toward the northern horizon.

December Night Sky

One of the more notable objects in Taurus, and indeed in the whole night sky, is a beautiful cloud of supernova debris know as the Crab Nebula or M1. The original supernova explosion was recorded by Japanese and Chinese astronomers nearly 1,000 years ago in 1054. The cloud of stardust is now around six light-years across and continues to expand - although not as fast as it did initially.

The intricate patterns you see are the remains of the atmosphere that once surrounded the large star (much bigger than our Sun) and are mostly made up of hydrogen gas. The central star had long since collapsed down to a tiny, unseen neutron star that now rotates over 30 times a second.

Mythology: Taurus

For over 5,000 years Taurus has been associated with a bull. Bulls have been worshipped since ancient times as symbols of strength and fertility. The ancient Egyptians worshipped Apis, the bull of Memphis, whilst the Israelites worshipped the Golden Calf. The Greeks, however, saw the constellation as Zeus (the God of Gods) disguised as a bull. Legend tells that Zeus fell in love with the beautiful Europa, daughter of Agenor, the King of Phoenicia. One day while playing at the waters edge, Europa's attention was caught by a magnificent white bull, Zeus in animal form. The bull knelt before her as she approached. She then climbed onto its back and placed flowers around its horns. Leaping to its feet, the bull took off into the sea and swam to Crete, where Zeus made Europa his mistress.