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If you are an early riser, look South-East at 6:30 AM local time - and there you will see the planets Venus and Jupiter very close together in the morning twilight!
Venus is the brighter of the two planets, and is heading closer and closer to the Sun every day.
The planet Mars is visible throughout the night this month – just look south for the brightest reddest object, high in the sky. Mars is visible from sunset until it heads towards the low western horizon at 1am.
On the evening of 15 February, the Moon is close to Mars, making it even easier to spot. But this meeting of the Moon and Mars only lasts a night, before the Moon continues on its monthly journey around the night sky.
The map to the left can help you find Mars by matching up the surrounding stars – the map shows you exactly what you will see when you look towards the south, before 10pm (after which, you have to start rotating the map significantly clockwise).
Mars is currently in the constellation of Taurus, and so is the red giant star, Aldebaran. Also in Taurus, is the Pleiades star cluster – a beautiful sight! Literally hundreds of stars are visible in binoculars. It often reminds me of a little desert-island of stars hidden in a vast sea of inky black space. It is the little cluster of stars at the far right of the map above.
The ringed planet Saturn is rising at 7pm in the East, close to the star Regulus in the constellation of Leo. As we look up to the night sky on the 20th, the Moon is very close to Regulus. Just to the East of the pair (that is, just to the left for northern hemisphere observers) you will find Saturn. Even a small telescope shows up the remarkable rings that surround the planet. Even though the rings of Saturn look solid through a telescope, they are made up of literally billions of fragments of rocks – some the size of dust, and the biggest ones the size of a small car.
Remember, the planets Mercury, Venus, Mars, Jupiter and Saturn all reflect so much light from the Sun that you can easily see them with your own eyes, albeit at various times of the year. That is why we've known about these planets for maybe 10,000 years or more. You've just missed out on seeing Mercury (it is next visible in the evening sky in May), but Jupiter and Venus can both be seen as the two bright points of light in the early morning sky – look east in the very early morning twilight.
And, finally, Orion is still prominent, with its nebula easily visible with your own eyes. As you look at the nebula though binoculars, even from the light pollution of London, you can see it is very different to the pin points of stars that surround it. Take a look through a telescope, and you get an even more impressive sight!
Two eclipses will be visible this month.
First, we have an annular solar eclipse occurring on 7 February 2008, visible in Antarctica and the very southern Pacific Ocean.
An annular eclipse occurs when the Sun and Moon perfectly align, but the Moon appears smaller than the Sun in the sky, leaving a ring of sunlight visible around the Moon. This is due to the Moon being slightly further away than usual in its elliptical orbit. If you have never seen an annular eclipse, click on the image to the left to see the time-lapse movie (in Windows Media Video format) of the 2005 annular eclipse, as visible from Madrid.
The eclipse is also visible in south-eastern Australia and New Zealand, as a partial solar eclipse. (A partial eclipse occurs when the Sun and Moon do not perfectly align.) In New Zealand, up to 65% of the Sun will be covered by the Moon.
A fortnight later, on 21 February, a lunar eclipse occurs on the opposite side of the sky (and so is visible on the opposite side of the Earth), once the Moon has moved around to the other side of the Earth - from being in-between the Earth and Sun, to being in the Earth's shadow. This lunar eclipse will be visible from Western Europe (including the UK), Western Africa, all of South America, and central and Eastern parts of both the USA and Canada. This lunar eclipse lasts from 00:30 until 6:20 GMT – basically, throughout the night!
Full details of both eclipses can be found at the NASA eclipse website.
But why do eclipses usually occur in pairs?
The Moon's orbit around the Earth is tilted by 5 degrees compared to the flat plane of the rest of our solar system. So the Moon is literally going above and then below the solar system. An eclipse can only happen when the Moon is moving up or down across the flat solar system, passing in front of the Sun – in astronomy terms, an eclipse can only happen when its nodal axis (see figure) is aligned with the Sun.
That is what will happen in February, and again about 6 months later, when the Earth has moved to the other side of the Sun, in August 2008.
If the Moon happens to pass through the Sun-side nodal axis (point 2) within 5 days of them aligning, then you get a total (or annular) eclipse of the Sun. If the Moon passes through this point within 15 days of the alignment, you will get a partial solar eclipse instead.
On the other side of the Earth, if the Moon passes through the shadow of the Earth (point 1), a lunar eclipse will occur. And you have about 10 days grace in which to do that, around the time that the nodal axis points at the Sun.
With all this leeway for getting an eclipse around the time the nodal axis points at the Sun, it is technically possible to get 3 eclipses in one month! This last occurred in July 2000, when there was a partial solar eclipse near Antarctica, then the Moon raced around to enter the heart of the Earth's shadow a fortnight later, and the month finished with another partial solar eclipse visible from near the Arctic.
For 84 years the major global news headlines of the day have been preceded by the six Greenwich Time 'pips'. When the news of Neil Armstrong’s first steps on the Moon, President John F Kennedy’s assassination, and the destruction of the Berlin Wall were broadcast across the world on the BBC, they followed the familiar sound of the Greenwich pips.
The six-pip Time Signal was introduced on 5 February following the successful broadcast of the chimes of Big Ben to usher in the new year of 1924. Late in 1923, Frank Dyson, ninth Astronomer Royal, visited John Reith, Director General of the BBC, to discuss the idea of public time signals being broadcast. The six-pip Time Signal (pips for seconds 55, 56, 57, 58, 59, 60) was Dyson’s brain-child, devised in discussion with Frank Hope-Jones, inventor of the free pendulum clock, who had originally advocated a five-pip signal.
In 1939, the six-pip signal and the Time Service moved from Greenwich to the magnetic observatory at Abinger in Surrey. They then moved to Herstmonceux, Sussex in 1957. In 1990, the Greenwich Time Signal transmitted its last pips. Since then the BBC has originated its own pips based on signals from the GPS satellite network and from the 60kHz radio transmitter at Anthorn, Cumbria, operated by VT Communications under contract to the National Physical Laboratory.
The original clock used for the six-pips signal is in the Time and Greenwich gallery at the Royal Observatory. This is currently closed for redecoration, but will reopen on 1 March 2008.
The clock is regulator number 2016 by Dent of London. It was made in 1874 for use across the globe when observing the Transit of Venus astronomical phenomenon that year, before moving to Greenwich. It was the very first to provide the six-pip signals in 1924 with pendulum roller contacts, which are still in the Observatory collection.
Here is a beautiful photograph of the 7 February solar eclipse, as seen from New Zealand. The photograph was taken by Andy Dodson and Deborah Hambly in New Zealand, where, as described in an earlier post, the Moon covered 59% of the Sun.
The photograph shows lots of activity around the limb of the Sun. These prominences are jets of hot gas, propelled outwards along the magnetic field lines of the Sun. Click on the image for a larger version.
The Space Shuttle Atlantis successfully docked with the International Space Station today - and you can see them fly overhead for yourself. The pair are astonishingly bright - all you need to do to see them is to look up at the right time!
You can see the space station rising in the West, flying over the South, before heading towards the East. It crosses the entire night sky in about 5 minutes. Remember - if it flashes, it's an aircraft, but if it has a constant brightness, then you are looking at a satellite. To confirm that you have seen a satellite, keep watching to see if it suddenly disappears into the shadow of the Earth.
The following table gives the (approximate) times (within 1-2 minutes) when the International Space Station is flying over the UK for the next week.
10 Feb, 18:34-18:38 GMT, peak 74° high
11 Feb, 17:20-17:25 GMT, peak 85° high
11 Feb, 18:55-18:58 GMT, peak 44° high
12 Feb, 17:40-17:46 GMT, peak 78° high
12 Feb, 19:15-19:18 GMT, peak 23° high
13 Feb, 18:01-18:06 GMT, peak 48° high
14 Feb, 18:21-18:26 GMT, peak 25° high
16 Feb, 17:27-17:32 GMT, peak 28° high
If you live outside the UK, see Heavens-above.com for times when the space station can be seen flying over your location.
The Royal Observatory has a new program of spring courses for the general public. You can learn how to take photographs of the night sky at our astrophotography workshop, or learn about the Big Bang and black holes at one of our monthly lectures.
Download the full programme of courses and talks as a PDF leaflet.
Most sky-watchers will recognise the familiar sight of Orion, the constellation which is dominating our view of the night sky at the moment.
But how would Orion look if we had X-ray eyes?
Objects at different temperatures give off light at different wavelengths. We can see this on the thermometer below. People are far too cold to give off visible light - we emit infrared light instead. Unfortunately, our eyes are not sensitive to infrared light, which is why we cannot see each other in the dark.
We humans rely on light originating from objects at a temperature of 2,000-12,000°C - objects that emit visible light. At 5,500°C, the Sun gives off plenty of visible light, as does a light bulb containing a filament glowing at up to 3,000°C.
But there are some things in our Universe that are much, much hotter... at millions of degrees Celsius.
From stars falling into black-holes, to neutrons stars speeding through space at 300,000 miles per hour; from supernovae explosions colliding with interstellar gas, to white dwarf stars being bombarded with a thousand million tonnes of gas… every second.
All of these (and more) emit X-ray radiation.
The slideshow below cycles through the familiar visible view of Orion, to the unfamiliar X-ray view of Orion.
The X-ray view of Orion was put together by Konrad Dennerl & Wolfgang Voges at MPE in 1995, to celebrate 5 years of ROSAT. Rosat was a German/US/UK X-ray space-telescope, that operated from 1990-1999.
When comparing the two views of Orion, pay particular attention to:
So the next time you gaze upon Orion, think how different it looks through X-ray eyes.
In the early hours of the morning of Thursday 21 February (the night of Wednesday 20 February) there will be a total lunar eclipse. The event will be visible from Western Europe (including the UK), Western Africa, all of South America, and central and Eastern parts of both the USA and Canada.
The times for the event are as follows:
But what are the penumbra and umbra shadows? Well, take a look at my tea mug to the left. As you can see, when I cast a shadow of the mug onto the desk using a lamp, there are two shadows - a lighter penumbra shadow, and a much darker umbra shadow. These two shadows are caused by the width of the light bulb (or Sun). If the light source was a tiny pin-point of light, there would only be one deep shadow.
As a taster, below is a time-lapse movie of a total lunar eclipse that occurred in 2006.
If, like me, you were clouded out last night, you can enjoy the lunar eclipse through the SpaceWeather.com gallery. The image to the left was taken last night by Mohammad Taher Pilevar, in Hamedan, Iran.
Eclipse totale de lune, 21 février 2008 /Total lunar eclipse, February 21 2008
Originally uploaded by Laurence_
Last night's eclipse has triggered a spate of activity on Flickr – total lunar eclipse was the most popular tag in the last 24 hours. We have picked out a few shots and saved them in our favourite photos, including the nice shot of the Moon against clouds above.
If you are interested in learning more about astrophotography, we are running a photography workshop on 4th March. Tickets are £15/£11 and must be booked in advance.
This page contains all entries posted to Royal Observatory, Greenwich in February 2008. They are listed from oldest to newest.
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