The Night Sky in December 2007
Sunrise and Sunset Times for the UK
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Edinburgh Sunrise Sunset |
Liverpool Sunrise Sunset |
London Sunrise Sunset | ||||
| December 01 | 8:19 AM | 3:45 PM | 8:04 AM | 3:58 PM | 7:43 AM | 3:55 PM |
| December 15 | 8:37 AM | 3:38 PM | 8:21 AM | 3:53 PM | 7:59 AM | 3:52 PM |
| December 30 | 8:44 AM | 3:46 PM | 8:28 AM | 4:01 PM | 8:06 AM | 4:00 PM |
Phases of the Moon (December 2007)
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| Last quarter Saturday 1st |
New Moon Sunday 9th |
First quarter Monday 17th |
Full Moon Monday 24th |
Last quarter Monday 31st |
Click HERE to see the phase of the Moon on each day of the month.
What's happening in the December night sky?
It's hard to believe that it's December already and that most of you will be gearing up for the festive period. There is no escaping the dark nights descending on us as we make our way home from school, and the days will continue to get shorter right up to the 22nd December; a day is known as the winter solstice (read more about it later). The good thing about the long dark nights is that we have the opportunity to get out in the back garden and explore the night sky.
Maps of the current night sky can be seen by clicking HERE
December 22nd - Winter Solstice (Shortest Day)
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 area 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.
December 24th - Occultation of Mars by the Moon
During the early hours of the 24th December at around 3:34 am, the combination of Mars close to opposition (where it is on the opposite side of Earth to the Sun) and December's full moon will create a fascinating spectacle for those in the very North of Scotland. The event, known as an occultation, will see the planet Mars disappearing behind the Moon for a few minutes.
Occultation Map
The above map shows the small area of the UK where the occultation will be visible. The graze line represents the area where Mars will only be partly hidden, i.e. it grazes the surface of the Moon. To the south of the line observers will see a close conjunction, and to the north they will see an occultation. The graze line runs from Stornoway, on the Isle of Lewis, through Inverness, across the Cairngorms and out past Arbroath. For the lucky few that live in the area, use the sky map below to locate where Mars and the Moon will be at 3am in the morning - just before the occultation takes place. You will probably need binoculars or a telescope to see things clearly.
Stellarium image showing the night sky around the Moon and Mars just before the occultation.
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.
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Mercury - starts
the month rising in the SouthEast around 45 minutes before the Sun. It continues to
move around behind the Sun and reaches a point called superior conjunction (on the
other side of the Sun to Earth) on the 17th. By the end of the month it will have
reappeared as an evening object, setting just 20 minutes after the Sun. However,
Mercury will be too dim (as it's way over on the other side of the Sun) to be seen
in the relative brightness of twilight. Therefore, very early December will be your
best chance to see it.
Venus - continues to shine brightly in the southeastern sky for several hours before sunrise and you will have no trouble finding it if you are an early riser. On the 1st, Venus rises in the EastSouthEast at around 3:50am, around 4.5 hours before the Sun. It gets slightly dimmer during the month as it moves slowly away from Earth. By the end of December it rises around 5am, and by the time the Sun gets up (around 8:40am) it will have reached high above the Southern horizon. Mars - starts the month rising in the NorthEast around 5:40pm, just 40 minutes after sunset. It then slowly crosses the night sky and can be found high above the Southern horizon at around 2am. Mars reaches opposition (on the other side of Earth to the Sun) on the 24th December, which means that December is the best month to observe Mars this year using Go Observing. By the end of the month Mars will rise just before sunset, can be found high above the Southern horizon around 11:40pm and then sets a little after sunrise. Why not use the Electric Orrery to see why December is a good time to observe Mars. Jupiter - is way over on the other side of the Sun and reaches conjunction (other side of the Sun to Earth) on the 23rd. It quite obviously didn't want to spend Christmas with us. Sadly, we won't be able to observe Jupiter with the Liverpool Telescope this month. For naked-eye observers, however, it may be possible to pick out Jupiter at the beginning of the month by looking low above the SouthWest horizon shortly after sunset. The first star-like object to appear in the twilight in that area will most likely be Jupiter. By the end of the month you can try the same again, but this time looking low above the SouthEast horizon shortly before sunrise - and I mean low. Saturn - rises in the EastNorthEast around 11:20pm at the beginning of December, so we have a good few hours to look for it before the Sun comes up. During the month we slowly catch Saturn up because of our closer (to the Sun) and therefore faster orbit. By the end of the month, Saturn will rise in the EastNorthEast at around 9:20pm and will have crossed the sky to reach high above the southern horizon by 4:20am. As these times get earlier, Saturn will become a better target to observe with the Liverpool Telescope. |
Best constellations to be seen in December 2007
Each month, we identify the best constellations to be seen from the UK between 9pm and 10pm.
This month we'll be looking for the winter constellations of Aries, Cetus,
Perseus and Triangulum,
which can be found towards the south in the
December night sky.
Night Sky in December
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Aries - is the Latin word for "ram". It is the 39th largest of the 88 modern
constellations and contains 2 bright stars, the brightest of which is Hamal. It is also one of
the 12 signs of the zodiac, because the Sun and planets all pass through it, as viewed from the Earth.
The best way to find Aries is to face South and locate the bright star Mira in the constellation
of Cetus (see below), which will be about a third the way up from the horizon to the Zenith -
the point right over your head. From there continue straight up to the next bright star, and that will
be the central brightest star a line of 3 visible stars that mark out Aries.
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Cetus - is named after a whale or sea monster that appeared in Greek mythology. It is the
4th largest constellation, and contains 3 bright stars and 12 dimmer ones. When looking towards Cetus
we are looking away from the plane of our galaxy, the
Milky Way, so our view is not blocked by the clouds of gas and dust
normally found in spiral galaxies. As such, we can see many hundreds of distant galaxies behind the
stars in Cetus, with each of those galaxies containing many millions of their own stars. To find Cetus,
face south around 9pm, and look up and right a bit. The first bright stars you come across will most likely
be part of the Cetus constellation, and you can use the above skymap to trace out all the other stars.
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Perseus - is named after the Greek hero who destroyed a legendary monster called the
Medusa - a monster that had hair made of snakes. In terms of size, it is the 24th largest
constellation and is blessed with 5 bright stars, the brightest of which is Mirfak. Mirfak
is known to be a giant star, some 62 times larger than the Sun and pumping out 5,000 times as much
energy. The second brightest star, Algol, is actually two stars orbiting each other every
3 days, but because they are so close they look like just one. At this time of year, Perseus can
be found right over the top of our heads at around 9pm, in a part of the night sky known as the
Zenith.
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Triangulum - is the Latin word for the shape it marks out in the night sky. It consists
of three relatively dim stars that form a long, narrow triangle. Being a small constellation, it is
only 78th largest and contains no bright stars, but should still be visible to the eye under a dark
sky - i.e. no bright Moon around and away from streetlights. Look for it by finding Aries first (see
above) and then look just above it for a small triangle.
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