Constellations and finding your way in the night sky

In short: Constellations are groups of stars in which people have seen figures for thousands of years. Today astronomy divides the whole sky into 88 defined constellations.

In more detail: In the 20th century the International Astronomical Union officially fixed the 88 constellations and their boundaries, so that every point in the sky belongs to exactly one constellation. Many names come from Greek and Roman mythology.

In detail

• Only from Earth: The stars of a constellation are usually not close to one another. They are often at very different distances and only look like a group from our point of view.
• The Plough: The well-known shape of the Plough, or Big Dipper, is not a constellation of its own but part of the Great Bear. Such striking patterns are called asterisms.
• Finding the Pole Star: If you extend the line through the two stars at the far end of the Plough’s bowl about five times, you reach the Pole Star. It sits almost exactly above the North Pole and so shows the direction of north.
• Seasons: Because the Earth travels around the Sun, different constellations are visible at night depending on the season. Orion, for example, is a typical winter constellation.
• Summer Triangle: The bright stars Vega, Deneb and Altair form a large triangle high in the summer sky and help with orientation.
• Southern sky: From the southern hemisphere you can see constellations that never rise in central Europe, such as the Southern Cross.
• Zodiac: The constellations through which the Sun appears to move during the year form the zodiac. Astronomically this also includes Ophiuchus, the Serpent Bearer, which astrology ignores.
• Astronomy, not astrology: Constellations are a practical system for organising the sky. There is no scientific evidence that they influence people’s fate.
• Good viewing: If you want to observe constellations, look for a dark place away from city lights (sterne-und-sternentwicklung, kompass-und-himmelsrichtungen, lichtverschmutzung-und-ihre-folgen).