There’s a misconception that if you want to get into stargazing and see anything in the night sky you have to spend money on high-tech equipment such as Go-To telescopes and CCD cameras. What if you just want to start with very basic astronomy and don’t want to buy anything? What can you see just by stepping outside and looking up?
Here, we’ll take you on a first night’s tour of the night sky in 10 easy steps…
Before you even look at the sky, take a look at yourself in the mirror. Are you dressed properly?
You’re going to be outside for at least an hour, hopefully longer, so dress appropriately for the cold, with a warm jacket, thick socks, gloves, scarf and a hat.
Basically, you want to look like one of the rosy-cheeked children playing happily in the winter snow from a vintage Ladybird book.
Choose your observing site
If you’re lucky you’ll be able to stargaze from your back garden, but it might not be the ideal place. Your garden could be surrounded by other houses, tall buildings and trees, which all reduce the amount of sky you can see.
And light pollution coming from nearby streetlights, pubs, shops and factories, and neighbours’ security lights, can take even more of your view away.
If this is the case, get away from all that. Head out of town to a dark spot in the countryside, or even just walk around the corner to your local park or school playing field.
It’ll make a big difference to what you can see.
Once you’ve found your observing site you’ll need to give your eyes time to get used to the darkness. Astronomers call this process ‘dark adaptation’ and it takes about half an hour.
After your eyes have relaxed, opened up their pupils to take account of the reduced light levels and released special chemicals to enhance their sensitivity, you won’t believe how many more stars you can see than when you first arrived.
Don’t browse on your phone while you wait; its bright screen will ruin your night vision.
You can see all the planets out to and including Saturn with your eyes alone, although they’re not all visible at the same time.
To the eye Venus is by far the brightest and fairest planet, shining like a beacon in the east when it’s the ‘Morning Star’ before sunrise, or in the west when it’s the ‘Evening Star’ after sunset.
The sky’s full of stars
Eyes successfully dark-adapted, you’ll notice that the sky is full of stars, many more than you ever see with just a glance from a light-polluted site.
You’ll realise that some stars are brighter than others, but before we look at why that is, a question: what are stars?
Well, the Sun is a star. It’s essentially just the closest star to Earth, a mere 146 million km away.
That’s very close in astronomical terms, but still so far away that the Sun’s light – travelling at 1,080,000,000 (1.08 billion) km/h – takes over eight minutes to reach us.
When the Sun sets we then see stars much further away, so far away that their light takes years, not minutes, to reach us.
Every star is a distant Sun and they are all different distances away from us. So a bright star is just closer to us than a faint star, right?
Well it’s not quite that simple. Like light bulbs, some stars are brighter and more powerful than others.
So just because a star is faint in the sky it doesn’t mean it’s a low power one; it might be a very luminous star a great distance from us. Likewise, a bright star in the sky might be a weak star that’s close.
You’ll see differences in the stars’ colours too. Most stars are an icy white colour, but after dark adapting your eyes you will make out that some are more of a bluish colour while others are yellow, orange or even red.
This is because stars have different temperatures. Blue stars are much hotter than orange stars, which makes sense if you consider the difference between a warm yellow candle flame and the fierce blue flame of a blow torch.
Stars aren’t just different brightnesses and colours. Some are smaller than our Sun, others are much larger, but those differences aren’t apparent to our naked eyes.
Patterns in the sky
Once you’re dark-adapted it won’t take you long to notice that the stars can be joined up to form patterns. You might recognise one straight away.
You may be able to see the giant saucepan-shaped Plough, balanced on the end of its handle.
But the Plough isn’t a constellation – it’s an asterism, a small pattern of stars immediately obvious to the naked eye.
The Plough forms part of the constellation of Ursa Major, the Great Bear. The Plough’s handle represents the bear’s tail, and fainter stars around it form the bear’s legs and head.
There are 88 constellations in the sky, but very few look like the person, animal or object they represent. You need a lot of imagination to recognise most of them!
How can you tell which bright stars are actually planets? There’s an easy way to tell them apart: stars twinkle, planets don’t.
This is because while stars are points of light, planets are tiny discs, so stars are affected more by the movement of the air, providing an answer to that oft-asked question ‘why do stars twinkle?’
The twinkling effect is something you can capture in a photograph showing the changing colours of a star.
If you see a bright ‘star’ that isn’t twinkling, it’s almost certainly a planet. But which one? We’ll tell you how to identify them later in this feature…
After a while you will almost certainly see a star dash across the sky: a meteor, or shooting star! These are tiny grains of space dust burning up in the atmosphere. Very bright ones, called fireballs, can drop meteorites on the ground.
Satellites look like faint stars and move much more slowly, taking a minute or more to cross the heavens.
The largest satellite, the International Space Station (ISS), can shine as brightly as Venus as it sails across the sky.
The stars move
If you stay at your observing site long enough you’ll notice that the stars which were low in the east when you arrived have climbed higher in the sky, and those which were low in the west are lower or might even have vanished from view altogether.
Why? It’s because as Earth rotates the stars appear to sweep across the sky.
Only one star stays still: Polaris, the Pole Star, which is aligned with Earth’s axis and can be found using the ‘Pointer’ stars in the Plough.
Return to your observing site in August or September and you’ll see the whole sky has changed. This is because the constellations we see change during the year, as Earth orbits the Sun.
Each season has its own constellations, which is why it takes a year to properly learn the sky and not just one night.
Download stargazing apps for your smartphone
Here are five planetarium apps that will help you around the night sky, but you’ll find plenty more in your app store. Turn your screen brightness right down or make it red to keep your night vision!
- Stellarium Mobile Free It’s missing the whistles and bells found on other apps, but Stellarium’s simulation of the night sky is beautifully realistic and gives a true impression of what the sky looks like.
- SkySafari The free version of this feature-packed planetarium app gives you all the information you need to plan your observing sessions, and enjoy eclipses and other astronomical events.
- Star Tracker A basic app that will help you identify stars, constellations and planets as you sweep your phone or tablet around the night sky. Beautiful graphics, but slightly annoying music.
- Mobile Observatory Free A powerful app with so many features it’s more like a full PC software package. Its renders of the night sky are realistic and useful for showing astronomical events in advance.
- Heavens-Above A very useful app that doesn’t simulate the stars or constellations like the others, but alerts you when the International Space Station and other satellites will be visible.
Get the kids involved
One of the best things about stargazing is that it isn’t just a hobby for adults, children can enjoy it too. Read our complete guide to getting kids involved in astronomy, or if your youngsters have already expressed and interest, it could be time to think about getting them their first telescope.
Don’t wait to get started
You don’t need to spend a fortune – or any amount of money – to start to enjoy stargazing as a hobby.
All you have to do is find somewhere away from bright lights, with a good view of the sky, and on your very first night you’ll see and learn a lot.
This article originally appeared in the February 2020 issue of BBC Sky at Night Magazine.