The Night Sky in January 2007

Sunrise and Sunset Times for the UK

	Edinburgh Sunrise Sunset		Manchester Sunrise Sunset		London Sunrise Sunset
Jan 01	08:44	15:48	08:25	15:59	08:06	16:02
Jan 15	08:35	16:09	08:18	16:19	08:00	16:20
Jan 30	08:13	16:39	07:59	16:46	07:43	16:45

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

Phases of the Moon


New Moon Friday 19th	First quarter Friday 26th	Full Moon Wednesday 3rd	Last quarter Thursday 11th

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

What's happening in the night sky?

Welcome to 2007! We hope you had a good Christmas and have recovered from all the chocolate and satsumas. With the arrival of the New Year we start to notice the days getting longer again, but thankfully there is still plenty of darkness to explore the night sky at a reasonable hour. If you do have the benefit of a crisp clear night, get out in the back garden and discover the beauty of the heavens.

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

January 3rd - Earth at perihelion

Orbit of Earth

At around 8pm on the evening of the 3rd January, the Earth will reach a point in its orbit around the Sun known as perihelion. This is the point when the Earth is closest to the Sun, and occurs because the Earth does not orbit in an exact circle. Instead, it moves in an elliptical path such that the distance from the Earth to the Sun changes slightly throughout the year. The perihelion distance this year will be 147.1 million km, increasing to 152.6 million km when it reaches Aphelion (furthest distance) on July 7th.

You may think that the Earth being closest to the Sun during our winter would cause it to be warmer. What we have to remember is that we (in the Northern Hemisphere) are also tilted away from the Sun, which means that we see alot less sunshine, and it is much colder as a result.

January 10th and 22nd - Moon at Apogee and Perigee

Orbit of Moon

In a similar way to the Earth having a slightly eccentric orbit, the Moon also moves closer and further away from the Earth during its 28 day orbit. The point of closest approach is known as perigee and furthest as apogee. In January 2007, these points equate to distances of 366,930 km and 404,333 km respectively.

Although the animation here is not to scale, it does show the relative 12% variation in the size of the Moon during the month. It is interesting to note that the Moon is gradually moving away from us over time. Around 1000 million years ago it was roughly half the distance away that it is today.

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 - starts its month lost in the glare of the morning sunrise as it moves towards superior conjunction (other side of the Sun to Earth) on the 7th Jan. It will then slowly emerge as an evening object, and by the 31st can be seen over the west-southwest horizon for around 90 minutes after sunset - but you will probably need binoculars to see it. Remember, planets don't "twinkle" like stars do - they shine more steadily.

Venus - is by far the brightest planet at the moment, and will remain an evening object right through until August 2007 as it slowly catches us up on its inside orbit. In early January it sets in the west-southwest around an hour after the Sun, increasing to nearly two hours by the month's end and outshining everything in the evening sky.

Mars - continues to move away from the Sun (as viewed from Earth) and will remain a morning object. At the start of the month it will appear low above the south-eastern horizon around 90 minutes before the Sun, although this will increase slowly 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 - continues to move clear of the Sun after passing behind it in late November. It is currently a morning object rising in the south-east around 6am, a couple of hours before the Sun, but this will come forward to 4.30am as we slowly catch Jupiter up on our inside track. By the end of the month, sunrise will find Jupiter low above the southern horizon. Although still further away than the Sun, next month should see Jupiter becoming a serious contender again as a suitable target to observe using the Liverpool Telescope.

Saturn - remains our primary target for getting reasonable images of a planet. At the start of the month it will rise in the east-northeast around 8pm and reach high above the southern horizon by 3am. Both these times move forward two hours by the 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 Cetus, the Great Whale, which can be found low above the southern horizon during the evening. The constellation can be a bit hard to identify, but try using the southerly pointing corners of the Great Square of Pegasus to direct you. Then look for the shape of a whale with its tail held aloft.

January Night Sky

One of the more notable objects in Cetus is a remarkable star called Mira. Mira is both an eclipsing binary, where two stars periodically block out the light from the other, and a star that varies dramatically in brightness over an average 331 day cycle. The period of the brightness changes is sometimes a little erratic and can be off by as much as 30 days. For about five months Mira is invisible, then over the next six months it gradually increases in brightness by up to 1500 times. The peak of brilliance lasts about a fortnight, after which it slowly starts to fade. That said, there have been some occasions when it has not been seen for several years.

It is now known that Mira is a highly evolved red giant star (Mira A) in the final stages of its lifetime. This is further complicated by the presence of a white dwarf companion star (Mira B). In this advanced red giant phase of Mira A's life, its diameter has swollen to about 600 times that of the Sun and it is pulsating, due to increasingly energetic nuclear reactions in its core. Mira A is now approaching the stage where its nuclear fuel supply will be run out, and it will collapse to become a white dwarf. In contrast, Mira B has already reached the white dwarf stage, and is about the size of the Earth, but around 250,000 times more massive.

From the images, it appears that Mira A is rapidly losing gas from its upper atmosphere, which is being pulled across by the gravity of Mira B. It then forms a swirling accretion disk of material around Mira B - a bit like the water swirling around a plug-hole - where very energetic collisions within the disk cause brief bursts of x-rays to be emitted, which can be detected by x-ray telescopes in orbit around Earth.

Mythology: Cetus

Cetus was the legendary sea monster that appeared in the tale of Cassiopeia, the legendary queen of Ethiopia, who upset the Sea Nymphs by bragging that she was more beautiful than them. The Sea Nymph's begged the God of the Sea, Poseidon, to punish the queen for her insults and conceit. Poseidon became so angry with Cassiopeia that he unleashed the horrible sea monster, Cetus the Whale, and sent him to destroy the coast of Cassiopeia's homeland.