AUDIO GUIDESAPRIL - JUNE

Hello everyone. I’m Dr Lucie Green, an astronomer with the Mullard Space Science Laboratory in Surrey.

Today, we’re going to be looking at some of the extraordinary stars and other objects that can be seen in the night skies over the UK during April, May and June 2013. As we move from winter to spring, the sky can appear less dramatic and the constellations rather more subtle. There’s plenty to see with the naked eye, but it’s well worth getting hold of a pair of binoculars or even a basic telescope if you can. Your local astronomical society will always be able to help you with this.

Most of the stars that we’re going to look at today are visible during the early evening. However, as the days become longer, you might find that you need to stay up later and later to be able to see the stars properly. This becomes more of an issue, the further north you go. So, if you’re based in Scotland and it’s getting towards the end of June, it’ll be nearly midnight before you can really start to appreciate what the night sky has to offer.

I’m going to show you how to use the sky’s natural signposts to find your way around the constellations. We’re also going to find out what constellations actually are, and even learn some basic astro-navigation – to help you get around without a compass or a sat nav, but just by using some of our amazing stars instead.

One of the most important collection of stars that can be seen from the UK has been given lots of different names over the centuries – the Plough, the Big Dipper or, my favourite, the Saucepan.

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The reason it’s such an important collection of stars is not just because it’s so easy to spot, but because it’s what is known as a circumpolar pattern for us. This means that, so long as the sky is dark and clear, it’s always visible from the UK – it does not set below the horizon, no matter what time of night it is and no matter the time of year.

You’ll usually find the Saucepan more or less overhead during the spring. The bowl of the pan is made up of four stars arranged as a distorted rectangle. A further three stars form the bent handle of the saucepan.

Lots of different cultures throughout history have recognised this distinctive arrangement of seven stars and told stories about it. Although the stars appear as a defined shape in the sky, this is simply what we call a line of sight effect. In reality, there are typically huge distances between each of the stars. In the case of the Saucepan, the two stars at either end of the pattern are more distant than the five in the centre.

The Saucepan pattern is what’s known as an asterism – that’s an unofficial pattern of stars. Patterns that have been officially recognised are known as constellations and there are 88 of them in the night sky. In modern times, the body responsible for defining constellations and their official boundaries is the International Astronomical Union.

The seven stars that make up the Saucepan are the brightest stars in a huge constellation known as Ursa Major, which means the Great Bear. The saucepan’s handle forms the bear’s tail which means that the left-hand side of the saucepan’s bowl forms – you guessed it – the bear’s backside!

The other two stars that form the bowl – that is, the ones furthest from the handle – are called the Pointers because they will lead you to one of the most useful stars for anyone in the northern hemisphere. If you imagine the saucepan the right way up, as though you were about to cook with it, extend the line the two Pointer stars make in an upwards direction.

Eventually, you’ll arrive at a lonely, middle-brightness star. This star has been given lots of names, including the North Star and Polaris.

Throughout history, sailors, shepherds, explorers and many other travellers have used Polaris to help them find their way around. Most stars appear to move across the sky but Polaris seems to remain in more or less the same place. What’s more, if you start at Polaris and drop an imaginary vertical line down to the horizon, this marks the direction of north. Turn to your left by 90 degrees and you’ll be facing west. Turn 90 degrees again so that north is behind you, and that’s south. Finally, one last turn by 90 degrees to the left and you’ll be facing east. Why don’t you use a compass to check? If you’ve done this correctly, you can congratulate yourself on carrying out your first bit of astro-navigation!

For other tips on making the most of the night sky go to bbc.co.uk/stargazing

And if you’ve got the stargazing bug, I’ll be back in July with a guide to the night sky for late summer and early autumn.

That’s all for now, I’m afraid. Good bye!