The sky is a map you can read
A constellation is not a group of stars but a region of sky — a way of finding your way around it. Pick one below, turn its outline on and off, and follow the same stars to the clusters and nebulae hidden among them.
Choose a constellation
Each chart can be panned and zoomed, with labelled primary stars and a toggleable outline.
Orion
The most recognisable constellation in the sky: three brilliant belt stars in a line, an orange shoulder and a blue-white foot. Orion is visible from almost everywhere on Earth and works as a signpost to half the winter sky.
Taurus
A zodiac constellation whose V-shaped face is anchored by orange Aldebaran, with two famous clusters hanging from its horns: the Pleiades and the Hyades. It is one of the oldest constellations, recorded on Babylonian tablets.
Andromeda
A long, straggling constellation of faint stars that holds the most famous object in the northern sky: the Andromeda Galaxy, M31. It shares a corner star with Pegasus, so the two constellations are often traced together.
Cassiopeia
Five bright stars forming a flattened W, circling the North Star and never setting from most northern latitudes. Cassiopeia is the easiest constellation to find after the Big Dipper.
Perseus
A curving chain of stars between Cassiopeia and the Pleiades, marking the hero who rescued Andromeda in the Greek myth. Perseus holds one of the sky's finest binocular sights: the Double Cluster.
Triangulum
A small but neatly drawn triangle of three stars between Andromeda and Aries. Its stars are modest, but its hidden treasure is enormous: the spiral galaxy M33.
Places in the Sky Worth Exploring
A young star cluster, a constellation full of landmarks, a nebula where stars are being born right now — and more added as the handbook grows. Each one sits inside our own galaxy and is visible in a dark sky or through a pair of binoculars.
The Pleiades
M45 · The Seven Sisters · ~444 light-years
The Pleiades is the most famous open star cluster in the sky — a tight gathering of hot blue stars in the constellation Taurus. To the naked eye most people count six or seven; binoculars reveal dozens, and a camera reveals the blue haze of dust that surrounds them.
Open this destinationOrion the Hunter
Constellation · Ori · Stars from ~250 to ~2,000 light-years
Orion is not an object in space but a pattern made by unrelated stars at very different distances. Its shape is so clear, and so evenly placed on the celestial equator, that astronomers and stargazers use it as a signpost to the rest of the sky.
Open this destinationThe Orion Nebula
M42 · NGC 1976 · ~1,344 light-years
M42 is the closest large region of active star formation to the Sun — a cloud of hydrogen, dust and newborn stars in the middle of Orion's Sword. Its glow comes from ultraviolet light pouring out of the young Trapezium Cluster, which ionises the surrounding gas and makes it shine.
Open this destinationWords that are often confused
A constellation is a region of sky, a cluster is a family of stars, a nebula is a cloud of gas and dust, and a galaxy is a whole city of stars. The words describe different things, at wildly different scales.
Constellation
e.g. Orion
A fixed region of sky, defined by the International Astronomical Union. The stars in a constellation usually lie at very different distances and are not physically related.
Star cluster
e.g. Pleiades (open)
A group of stars born from the same cloud and still bound by gravity. Open clusters are young and loose; globular clusters are ancient and tightly packed.
Nebula
e.g. Orion Nebula
A cloud of gas and dust inside a galaxy. Emission nebulae glow because hot young stars ionise them; reflection nebulae scatter starlight; dark nebulae block it.
Galaxy
e.g. Andromeda (M31)
An enormous gravitationally bound system of stars, gas, dust and dark matter — containing billions of stars, and often many nebulae and clusters of its own.
| Object | What it is | Distance | Across | Made of | Looks like |
|---|---|---|---|---|---|
| The Pleiades | Open star cluster | ~444 ly | ~8 ly across | ~1,000 hot young stars born together, plus dust | Tight sparkle of blue stars, often six to nine naked-eye points |
| Orion Nebula (M42) | Emission nebula + embedded cluster | ~1,344 ly | ~24 ly across | Hydrogen gas, dust, and newborn stars including the Trapezium | Fuzzy greenish-white cloud around a small group of stars |
| Andromeda Galaxy | Spiral galaxy | ~2.5 million ly | ~220,000 ly across | Billions of stars, gas, dust, dark matter — and its own clusters and nebulae | A faint elongated smudge; binoculars show a bright core and two companions |
The key distinction: a nebula and a star cluster live inside a galaxy. A galaxy is the galaxy — billions of stars, gas and dust held together by gravity, often containing many nebulae and clusters of its own. All distances are in light-years (ly).
Sources & credits
Star charts are drawn for ANDROMEDA from approximate catalogue positions and are schematic. Deep-sky images are artist's impressions, not telescope photographs.
Figures are rounded averages from NASA, ESA and IAU reference data. Star positions on charts are schematic and approximate.
Ready for a knowledge check?
Five questions on constellations, star charts and how to read them.