Stargazing for beginners and how to find the main constellations
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Hold your fist out at arm's length and it covers about 10° of sky. The full Moon, which looks so large, is only about half a degree across; your little finger hides it completely. A hand, a clear night and a few well-known star patterns are all you need to begin.
This guide is written for the Northern Hemisphere, including the UK and most of the USA. Further south, some of these patterns sit low or out of sight, and others, such as the Southern Cross, take their place.
Before you go out
- Go with an adult, and make sure someone at home knows where you are.
- Dress warmly. Standing still on a clear night gets cold, even in summer.
- Give your eyes time. It takes about 20 to 30 minutes in the dark for your eyes to reach full sensitivity. One glance at a bright screen undoes much of it.
- Use red light. Cover a torch with red cellophane or use a red-light setting; red light disturbs night vision far less than white.
- Choose your night. A moonless night away from street lights shows far more stars. Near full moon only the brighter ones stand out.
Your hand as a ruler
| At arm's length | Approximate angle |
|---|---|
| Width of your little finger | 1° |
| Width of three middle fingers | 5° |
| Closed fist | 10° |
| Spread hand, thumb tip to little finger tip | 20° |
Hands and arms grow together, so these rough figures work for children and adults alike.
Step 1: find the Plough
The Plough (the Big Dipper in North America) is seven bright stars shaped like a saucepan with a long, bent handle. It is part of the constellation Ursa Major, the Great Bear. Strictly, the Plough is an asterism, a recognisable pattern within a constellation, rather than a constellation itself.
From the UK the Plough never sets, so it is there on every clear night. It does swing round the sky, though: high overhead on spring evenings and low in the north on autumn evenings.
Step 2: from the Plough to Polaris
The two stars at the end of the pan, furthest from the handle, are the Pointers. Follow the line from the bottom one through the top one and carry on for about five times the gap between them. You arrive at a moderately bright star on its own: Polaris, the Pole Star.
Polaris is only about the 50th brightest star in the sky, so it is easy to underestimate. What makes it special is its position, almost directly above the Earth's North Pole. As the Earth turns, every other star appears to circle around it while Polaris barely moves. Face Polaris and you are facing north.
Worked example: how high is Polaris?
The height of Polaris above the horizon is roughly equal to your latitude. From a town at 52° N:
- Polaris should be about 52° up.
- A fist is about 10°, so that is a little over five fists above the northern horizon.
Count about five fists up and find a lone star, and you have probably found it. The link between Polaris and latitude is explained in how latitude and longitude work.
Step 3: Cassiopeia, the W
On the opposite side of Polaris from the Plough is Cassiopeia, five stars in a W or M shape depending on the time of year. It never sets from the UK either. When the Plough is low and hard to see, Cassiopeia is high, and the other way round, so one of them is always there to help.
Step 4: Orion and its signposts
From about November to March, the southern sky in the evening is dominated by Orion. Look for three stars in a short, straight row: Orion's Belt. Above and below it, four bright stars mark the hunter's shoulders and knees.
- Betelgeuse, at the top left, is a red supergiant, and its orange tint is visible to the eye.
- Rigel, at the bottom right, is blue-white. The colours are a clue to temperature, as our article on the life cycle of stars explains.
The Belt also works as a pointer. Follow it down and to the left to reach Sirius, the brightest star in the night sky. Follow it up and to the right to reach the orange star Aldebaran, and beyond it a small, misty cluster, the Pleiades or Seven Sisters.
Summer: the Summer Triangle
On summer and early autumn evenings, look high up for three bright stars forming a large triangle: Vega, Deneb and Altair. Each is the brightest star in its own constellation. From a dark site, the faint band of the Milky Way runs through the triangle.
Star, planet, satellite or aircraft?
| What you see | Clues |
|---|---|
| Star | Fixed in its pattern; often twinkles, especially near the horizon |
| Planet | Bright and steadier; not part of any familiar pattern; shifts position over weeks |
| Satellite | A steady point gliding smoothly across the sky in a few minutes, without flashing |
| Aircraft | Flashing lights, often red and green; may be heard |
| Meteor | A streak lasting a second or less |
Stars twinkle because their light passes through moving layers of air. Planets are close enough to show as tiny discs, so their light is steadier. The brightest satellite is the space station; see the International Space Station for how to catch it.
Stars in a constellation only look close together. The stars of Orion lie at very different distances from us, and the pattern exists only from our point of view.
Safety: never point binoculars or a telescope anywhere near the Sun, even when it is low at sunset. It can blind you instantly.
Activity: a star diary
- On dark paper, mark Polaris in the centre with white crayon or chalk.
- Draw the Plough and Cassiopeia where you see them, on opposite sides.
- Go out again two hours later and redraw them. Which way have they turned around Polaris?
- Add any planets or satellites you see, with the time.
If you would rather start from a printed template, the free printables on EduPrintables include blank pages you can adapt for a star diary.
Frequently asked questions
How many constellations are there?
The International Astronomical Union recognises 88, which together cover the whole sky like countries on a map. Many names come from ancient Greek and Roman stories; some southern ones were named by European astronomers and navigators from the 1500s onwards.
Do I need a telescope?
Not to start. Ordinary binoculars are an excellent next step at night: they show craters on the Moon, the four largest moons of Jupiter as tiny dots, and many more stars in the Milky Way.
When is the best time to see shooting stars?
During a meteor shower. Two of the best each year are the Perseids, which peak around 12 August, and the Geminids, around 13 to 14 December. Lie back, look at a wide patch of sky and be patient.
Why do the constellations change through the year?
As the Earth travels around the Sun, the night side of the planet faces a different part of space. That is why Orion fills winter evenings while the Summer Triangle takes over in July and August.
Sources and further reading
- Skywatching – NASA Science – monthly sky guides and tips for spotting planets, meteor showers and the Moon.
- The constellations – International Astronomical Union – the official list of the 88 constellations and their names.
- Spot the Station – NASA – times when the International Space Station passes over your area.
