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Seasons and Patterns

seasonsconstellationsImage: In different seasons we see different parts of the night sky. As the Earth moves around the Sun, the dark side of the Earth is directed towards different constellations. This image shows the constellations of the Zodiac (along the ecliptic) that we see in different parts of the year.

In our southern sky typical Summer constellations are Hydrus, Mensa and Volans. Typical Winter Constellations are Triangulum Australe, Norma, and Circinus.



Proper motion

Stars move at high speed through space in different directions. But because they are so extremely far away, we don't see any change in relative positions between stars in a human lifetime.

But on geologic time scales, a constellation’s pattern will slowly change due to what is called “proper motion”, as is shown here for the Big Dipper. These changes are only noticeable over tens of thousands of years.






Big Dipper 150,000 BCE to 150,000 CE

This animated image is generated by SkyChart III showing the movement of stars in and around the Big Dipper over a period of 300,000 years, starting from the year 150,000 BCE. Each frame of the animation represents 1000 years.








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