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The Starry Sky — the Great Book of Nature

A science lesson for grades 3–4: what constellations are, how to find Polaris, why stars are different colors and which constellations can be seen in winter and in summer. With tasks on the interactive sky map — you can open it on a projector in class or at home.

  • 8tasks on the sky map
  • 5“test yourself” questions
  • 3–4grades
To the tasksOpen the sky map
How to find Polaris: a line through the two end stars of the Big Dipper’s bowl Arcturus, Boötes — magnitude −0.1. Open on the sky mapCapella, Auriga — magnitude 0.1. Open on the sky mapPollux, Gemini — magnitude 1.2. Open on the sky mapCastor, Gemini — magnitude 1.6. Open on the sky mapAlioth, Ursa Major — magnitude 1.8. Open on the sky mapDubhe, Ursa Major — magnitude 1.8. Open on the sky mapDubheAlkaid, Ursa Major — magnitude 1.9. Open on the sky mapMenkalinan, Auriga — magnitude 1.9. Open on the sky mapPolaris, Ursa Minor — magnitude 2.0. Open on the sky mapPolarisKochab, Ursa Minor — magnitude 2.1. Open on the sky mapMizar, Ursa Major — magnitude 2.2. Open on the sky mapEltanin, Draco — magnitude 2.2. Open on the sky mapMerak, Ursa Major — magnitude 2.3. Open on the sky mapMerakIzar, Boötes — magnitude 2.4. Open on the sky mapPhecda, Ursa Major — magnitude 2.4. Open on the sky mapMuphrid, Boötes — magnitude 2.7. Open on the sky mapAthebyne, Draco — magnitude 2.7. Open on the sky mapRastaban, Draco — magnitude 2.8. Open on the sky mapCor Caroli, Canes Venatici — magnitude 2.9. Open on the sky mapAlgenubi, Leo — magnitude 3.0. Open on the sky mapψ Ursae Majoris — magnitude 3.0. Open on the sky mapPherkad, Ursa Minor — magnitude 3.0. Open on the sky mapTania Australis, Ursa Major — magnitude 3.1. Open on the sky mapTalitha, Ursa Major — magnitude 3.1. Open on the sky mapθ Ursae Majoris — magnitude 3.2. Open on the sky mapMegrez, Ursa Major — magnitude 3.3. Open on the sky mapMuscida, Ursa Major — magnitude 3.4. Open on the sky mapTania Borealis, Ursa Major — magnitude 3.5. Open on the sky mapAlula Borealis, Ursa Major — magnitude 3.5. Open on the sky mapAlkaphrah, Ursa Major — magnitude 3.6. Open on the sky maph Ursae Majoris — magnitude 3.6. Open on the sky mapTaiyangshou, Ursa Major — magnitude 3.7. Open on the sky mapυ Ursae Majoris — magnitude 3.8. Open on the sky mapAlula Australis, Ursa Major — magnitude 3.8. Open on the sky mapAlcor, Ursa Major — magnitude 4.0. Open on the sky mapCircitores, Ursa Minor — magnitude 4.2. Open on the sky map5 Ursae Minoris — magnitude 4.3. Open on the sky mapAkfa Farkadain, Ursa Minor — magnitude 4.3. Open on the sky mapYildun, Ursa Minor — magnitude 4.3. Open on the sky mapAlhaud, Ursa Major — magnitude 4.5. Open on the sky map26 Ursae Majoris — magnitude 4.5. Open on the sky mapd Ursae Majoris — magnitude 4.5. Open on the sky mapφ Ursae Majoris — magnitude 4.5. Open on the sky mapMuseida, Ursa Major — magnitude 4.6. Open on the sky map N ↑← E
The dotted line is the way from the Big Dipper to Polaris.

What a constellation is

On a clear night far from the city, the naked eye can see about three thousand stars at once. So as not to get lost among them, since ancient times people have grouped bright stars into patterns and given them names — the Great Bear, the Swan, Orion. These patterns are called constellations.

Today the whole sky is divided into 88 constellations with exact borders, like a map divided into countries. The stars of one constellation only seem to be neighbors: in fact some of them are much farther away than others.

Ursa Major and Polaris

The seven bright stars of Ursa Major form a dipper with a handle — it is easy to recognize. At mid-northern latitudes the Dipper never sets below the horizon: it can be seen on any clear night, it is just turned differently.

Draw a line through the two end stars of the Dipper’s bowl — Merak and Dubhe — and extend it about five times that distance. It leads to Polaris, the last star in the handle of the Little Dipper in Ursa Minor. Polaris stands almost exactly above the Earth’s axis, so it stays in place all night and shows where north is, while the other stars circle around it.

On the other side of Polaris are the five stars of Cassiopeia, shaped like the letter W.

The constellation Cassiopeia in the starry sky: its figure and its bright stars Navi, Cassiopeia — magnitude 2.1. Open on the sky mapNaviShedar, Cassiopeia — magnitude 2.2. Open on the sky mapShedarCaph, Cassiopeia — magnitude 2.3. Open on the sky mapCaphRuchbah, Cassiopeia — magnitude 2.7. Open on the sky mapSegin, Cassiopeia — magnitude 3.4. Open on the sky mapAchird, Cassiopeia — magnitude 3.5. Open on the sky mapFulu, Cassiopeia — magnitude 3.7. Open on the sky mapκ Cassiopeiae — magnitude 4.2. Open on the sky mapMarfak, Cassiopeia — magnitude 4.3. Open on the sky mapρ Cassiopeiae — magnitude 4.5. Open on the sky map N ↑← E
Cassiopeia — a “W” on the other side of Polaris from the Dipper.

Stars of different colors

Stars are distant suns, huge glowing balls of hot gas. They come in different colors, and the color tells you the temperature: reddish stars are cooler, yellow ones are like our Sun, and white and blue ones are the hottest. This is easiest to see in winter in Orion: Betelgeuse in its “shoulder” is reddish, while Rigel in its “foot” is bluish white.

Orion and Taurus: Betelgeuse, Rigel, Aldebaran and the Pleiades Rigel, Orion — magnitude 0.2. Open on the sky mapRigelBetelgeuse, Orion — magnitude 0.5. Open on the sky mapBetelgeuseAldebaran, Taurus — magnitude 0.9. Open on the sky mapAldebaranBellatrix, Orion — magnitude 1.6. Open on the sky mapElnath, Taurus — magnitude 1.6. Open on the sky mapAlnilam, Orion — magnitude 1.7. Open on the sky mapAlnitak, Orion — magnitude 1.7. Open on the sky mapAlhena, Gemini — magnitude 1.9. Open on the sky mapSaiph, Orion — magnitude 2.1. Open on the sky mapMintaka, Orion — magnitude 2.3. Open on the sky mapMenkar, Cetus — magnitude 2.5. Open on the sky mapHatysa, Orion — magnitude 2.8. Open on the sky mapCursa, Eridanus — magnitude 2.8. Open on the sky mapAtik, Perseus — magnitude 2.8. Open on the sky mapAlcyone, Taurus — magnitude 2.9. Open on the sky mapAlcyoneTejat, Gemini — magnitude 2.9. Open on the sky mapZaurak, Eridanus — magnitude 3.0. Open on the sky mapTianguan, Taurus — magnitude 3.0. Open on the sky mapTabit, Orion — magnitude 3.2. Open on the sky mapSaif al Jabbar, Orion — magnitude 3.4. Open on the sky mapMeissa, Orion — magnitude 3.4. Open on the sky mapChamukuy, Taurus — magnitude 3.4. Open on the sky mapλ Tauri — magnitude 3.4. Open on the sky mapAin, Taurus — magnitude 3.5. Open on the sky mapτ Orionis — magnitude 3.6. Open on the sky mapο Tauri — magnitude 3.6. Open on the sky mapAtlas, Taurus — magnitude 3.6. Open on the sky mapPrima Hyadum, Taurus — magnitude 3.6. Open on the sky mapπ⁴ Orionis — magnitude 3.7. Open on the sky mapπ⁵ Orionis — magnitude 3.7. Open on the sky mapElectra, Taurus — magnitude 3.7. Open on the sky mapξ Tauri — magnitude 3.7. Open on the sky mapSecunda Hyadum, Taurus — magnitude 3.8. Open on the sky mapσ Orionis — magnitude 3.8. Open on the sky mapθ¹ Tauri — magnitude 3.8. Open on the sky mapMaia, Taurus — magnitude 3.9. Open on the sky mapν Tauri — magnitude 3.9. Open on the sky mapο² Orionis — magnitude 4.1. Open on the sky mapφ² Orionis — magnitude 4.1. Open on the sky mapμ Orionis — magnitude 4.1. Open on the sky mape Orionis — magnitude 4.1. Open on the sky mapf Tauri — magnitude 4.1. Open on the sky mapMerope, Taurus — magnitude 4.1. Open on the sky map32 Orionis — magnitude 4.2. Open on the sky mapκ Tauri — magnitude 4.2. Open on the sky mapd Tauri — magnitude 4.3. Open on the sky mapμ Tauri — magnitude 4.3. Open on the sky mapc¹ Tauri — magnitude 4.3. Open on the sky mapτ Tauri — magnitude 4.3. Open on the sky mapυ Tauri — magnitude 4.3. Open on the sky map10 Tauri — magnitude 4.3. Open on the sky mapTaygeta, Taurus — magnitude 4.3. Open on the sky map68 Tauri — magnitude 4.3. Open on the sky mapThe Ruby Star, Taurus — magnitude 4.3. Open on the sky mapAl Taj, Orion — magnitude 4.3. Open on the sky mapA¹ Tauri — magnitude 4.4. Open on the sky mapHeka, Orion — magnitude 4.4. Open on the sky mapχ¹ Orionis — magnitude 4.4. Open on the sky mapν Orionis — magnitude 4.4. Open on the sky mapξ Orionis — magnitude 4.5. Open on the sky mapρ Orionis — magnitude 4.5. Open on the sky mapπ⁶ Orionis — magnitude 4.5. Open on the sky map71 Tauri — magnitude 4.5. Open on the sky mapω Orionis — magnitude 4.5. Open on the sky mapHIP 28413, Orion — magnitude 4.5. Open on the sky map136 Tauri — magnitude 4.6. Open on the sky mapMizan Batil, Orion — magnitude 4.6. Open on the sky mapψ Orionis — magnitude 4.6. Open on the sky map N ↑← E
Orion with the three stars of its belt; next to it, Taurus with orange Aldebaran and the Pleiades.

The winter and summer sky

Over a year the Earth goes around the Sun, and at night we look in a different direction each time. That is why each season has its own constellations. On winter evenings, in the south, there are Orion, Taurus and the brightest star in the sky — Sirius in Canis Major. In summer, high overhead, is the Summer Triangle of three bright stars: Vega in Lyra, Deneb in Cygnus and Altair in Aquila.

The Summer Triangle: Vega, Deneb and Altair Vega, Lyra — magnitude 0.0. Open on the sky mapVegaAltair, Aquila — magnitude 0.8. Open on the sky mapAltairDeneb, Cygnus — magnitude 1.3. Open on the sky mapDenebRasalhague, Ophiuchus — magnitude 2.1. Open on the sky mapSadr, Cygnus — magnitude 2.2. Open on the sky mapEltanin, Draco — magnitude 2.2. Open on the sky mapEnif, Pegasus — magnitude 2.4. Open on the sky mapScheat, Pegasus — magnitude 2.4. Open on the sky mapAljanah, Cygnus — magnitude 2.5. Open on the sky mapMarkab, Pegasus — magnitude 2.5. Open on the sky mapTarazed, Aquila — magnitude 2.7. Open on the sky mapCebalrai, Ophiuchus — magnitude 2.8. Open on the sky mapKornephoros, Hercules — magnitude 2.8. Open on the sky mapRasalgethi, Hercules — magnitude 2.8. Open on the sky mapRastaban, Draco — magnitude 2.8. Open on the sky mapζ Herculis — magnitude 2.8. Open on the sky mapFawaris, Cygnus — magnitude 2.9. Open on the sky mapSadalsuud, Aquarius — magnitude 2.9. Open on the sky mapMatar, Pegasus — magnitude 2.9. Open on the sky mapSadalmelik, Aquarius — magnitude 3.0. Open on the sky mapOkab, Aquila — magnitude 3.0. Open on the sky mapAlbireo, Cygnus — magnitude 3.0. Open on the sky mapζ Cygni — magnitude 3.2. Open on the sky mapθ Aquilae — magnitude 3.2. Open on the sky mapSulafat, Lyra — magnitude 3.3. Open on the sky mapAlmizan, Aquila — magnitude 3.4. Open on the sky mapAl Thalimain Prior, Aquila — magnitude 3.4. Open on the sky mapSheliak, Lyra — magnitude 3.5. Open on the sky mapAlshain, Aquila — magnitude 3.7. Open on the sky mapξ Cygni — magnitude 3.7. Open on the sky mapτ Cygni — magnitude 3.7. Open on the sky mapι Cygni — magnitude 3.8. Open on the sky mapFawaris, Cygnus — magnitude 3.8. Open on the sky mapο¹ Cygni — magnitude 3.8. Open on the sky mapη Aquilae — magnitude 3.9. Open on the sky mapη Cygni — magnitude 3.9. Open on the sky mapν Cygni — magnitude 3.9. Open on the sky mapο² Cygni — magnitude 4.0. Open on the sky mapρ Cygni — magnitude 4.0. Open on the sky map41 Cygni — magnitude 4.0. Open on the sky mapDeneb al Okab Borealis, Aquila — magnitude 4.0. Open on the sky mapi Aquilae — magnitude 4.0. Open on the sky map13 Lyrae — magnitude 4.1. Open on the sky mapδ² Lyrae — magnitude 4.2. Open on the sky map52 Cygni — magnitude 4.2. Open on the sky mapσ Cygni — magnitude 4.2. Open on the sky mapπ² Cygni — magnitude 4.2. Open on the sky map33 Cygni — magnitude 4.3. Open on the sky mapl Aquilae — magnitude 4.3. Open on the sky mapκ Lyrae — magnitude 4.3. Open on the sky mapNasr Alwaki, Lyra — magnitude 4.3. Open on the sky mapθ Lyrae — magnitude 4.3. Open on the sky mapAl Thalimain Posterior, Aquila — magnitude 4.4. Open on the sky mapυ Cygni — magnitude 4.4. Open on the sky mapAladfar, Lyra — magnitude 4.4. Open on the sky map39 Cygni — magnitude 4.4. Open on the sky mapμ Aquilae — magnitude 4.5. Open on the sky mapθ Cygni — magnitude 4.5. Open on the sky mapμ¹ Cygni — magnitude 4.5. Open on the sky mapλ Cygni — magnitude 4.5. Open on the sky mapf² Cygni — magnitude 4.6. Open on the sky mapε² Lyrae — magnitude 4.6. Open on the sky map N ↑← E
The Summer Triangle: Vega, Deneb and Altair.

The Sun’s path across the sky passes through twelve constellations — they are called the zodiac constellations: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, Capricornus, Aquarius and Pisces. By the borders approved by astronomers, the Sun also passes through Ophiuchus.

Tasks on the sky map

Each task opens the sky map at the right constellation or star. The answer is hidden under a button — first try to find it yourself.

  1. 1

    Find Ursa Major on the map. How many stars are there in its Dipper, bowl and handle together?

    Open on the map
    Answer

    Seven: four stars form the bowl and three the handle. The Great Bear itself is bigger than the Dipper: the Dipper is its back and tail.

  2. 2

    Draw a line through the two end stars of the bowl — Merak and Dubhe — and extend it about five times that distance. Which star does it lead to?

    Open on the map
    Answer

    To Polaris — the last star in the handle of the Little Dipper. Polaris shows where north is.

  3. 3

    Set the map’s time speed to “×3600” and watch Polaris. What happens to the stars around it?

    Open on the map
    Answer

    All the stars circle around Polaris counterclockwise, while Polaris itself hardly moves: it stands almost exactly above the Earth’s axis. In fact it is the Earth that rotates; the sky only seems to turn.

  4. 4

    Find the constellation Cassiopeia. Which letter does it look like?

    Open on the map
    Answer

    The letter W (or M, depending on how the sky is turned). Cassiopeia is on the other side of Polaris from the Big Dipper.

  5. 5

    Find Orion. What color are its stars Betelgeuse and Rigel?

    Open on the map
    Answer

    Betelgeuse is reddish, Rigel is bluish white. A star’s color tells you its temperature: red stars are cooler, blue ones are hotter.

  6. 6

    Find the constellation Taurus next to Orion. What is its brightest star called, and what is the little group of stars nearby?

    Open on the map
    Answer

    Aldebaran — an orange star, the “eye of the Bull”. The little group of stars is the Pleiades, a star cluster: the naked eye can see six or seven stars in it.

  7. 7

    Find the Summer Triangle — three bright stars, Vega, Deneb and Altair. Which constellations are they in?

    Open on the map
    Answer

    Vega is in Lyra, Deneb in Cygnus, Altair in Aquila. In summer and early autumn the triangle is high in the south in the evening.

  8. 8

    Set the map to your city and this evening, 21:00. Which planets are above the horizon?

    Open the map Planets today
    Answer

    The answer depends on the date. You can check yourself on the “Planets in the sky today” page — it calculates which planets can be seen tonight.

Test yourself

What is a constellation?

An area of the sky with a pattern of bright stars. People invented the patterns in ancient times, and now the whole sky is divided into 88 constellations with exact borders.

Why can’t we see stars in the daytime?

Their light is lost in the bright light of the sky: the air scatters sunlight, and the sky becomes blue and bright. The stars themselves don’t go anywhere.

Why do stars look like tiny dots?

They are very far away. Even the nearest star after the Sun is so far away that its light takes more than four years to reach us.

Which star is the closest to the Earth?

The Sun. It is an ordinary star, just very close to us.

Why is the starry sky called the great book of nature?

Since ancient times people have used the stars to tell the season, the directions and the way. Constellations are like the pages of this book: once you learn to recognize them, you can “read” the sky.

For teachers

The sky map works in the browser with no installation or sign-up — on a computer with a projector, on an interactive whiteboard, on tablets and phones. Set the school’s city and an evening time: the pupils will see the same sky as above their homes in the evening. The “×3600” time speed shows in a minute how the sky turns around Polaris; clicking a constellation opens its card with a hint on how to find it. The pages on constellations, “Moon today” and “Planets in the sky” are useful for observing at home.

Questions

How do you find Polaris?

Find the Big Dipper, draw a line through the two end stars of its bowl — Merak and Dubhe — and extend it about five times that distance. The line will reach Polaris, the last star in the handle of the Little Dipper.

How many constellations are there?

Eighty-eight. Their list and borders were approved by the International Astronomical Union in the 1920s. From 40° N, 73 of them can be seen at least in part; from 52° N, 65.

Why are stars different colors?

A star’s color depends on the temperature of its surface: red stars are the coolest, yellow ones (like the Sun) are hotter, and white and blue ones are the hottest.

How do you teach a “Starry Sky” lesson with the sky map?

Open the map on a projector and set the school’s city and an evening time. Turn on the “×3600” time speed to show how the sky turns around Polaris, and click a constellation to open its card with a hint on how to find it. The lesson’s tasks lead straight to the right place on the map.

Find it in the sky tonightA sky map over your city: constellations, the Moon, planets and the ISS at any moment.
Open the sky map