1. O North Pole The time is mid-day. The observer O at the equator looks straight up and sees the sun overhead. Sun Serpens Pisces Orion Leo

2. North Pole Six hours later, the earth has turned through 90 o. The observer has to look towards the horizon (i.e. horizontally) to see the sun. Sun Serpens Pisces Orion Leo Direction of the sun

3. North Pole From the observer’s point of view, the sun has gone from overhead down to the western horizon. Sun Serpens Pisces Orion Leo Direction of the sun

4. North Pole Now, if he looks overhead, he sees the constellation Pisces. Orion is just appearing at the eastern horizon. Sun Serpens Pisces Orion Leo Direction of the sunDirection of Orion

5. North Pole After another 6 hours it is midnight. The observer sees Orion straight overhead. O Sun Serpens Pisces Orion Leo

6. North Pole Pisces has reached the western horizon and Leo is just appearing at the eastern horizon. O Sun Serpens Pisces Orion Leo Direction of Leo Direction of Pisces

7. North Pole Orion has moved up from the eastern horizon to the zenith (overhead). O Sun Serpens Pisces Orion Leo Direction of Leo Direction of Pisces

8. North Pole At dawn, the observer can see Orion at the western horizon and the sun is rising in the east. Leo is now overhead. Sun Serpens Pisces Orion Leo Direction of OrionDirection of sunrise

9. North Pole As seen from “above” the north pole, the earth rotates counterclockwise. To an observer on the earth, the sky appears to move clockwise – i.e. from east to west. Sun Serpens Pisces Orion Leo Rotation of earth Apparent rotation of sky

10. During the course of a night, half of the entire sky can be seen. Which half depends on where the earth is in its orbit. The other half of the sky is still there, but it is not bright enough to see during the daytime.

11. Something similar happens during the year.

12. Sun Serpens Pisces Orion Leo Position of Earth in December Position of Earth in September Position of Earth in June Position of Earth in March

13. Sun Serpens Pisces Orion Leo Position of Earth in December In December, Orion is overhead at midnight. Pisces is setting on the western horizon and Leo is rising in the east. Serpens cannot be seen because of the daylight.

14. Sun Serpens Pisces Orion Leo Position of Earth in March In March, Leo is overhead at midnight. Orion is setting on the western horizon and Serpens is rising in the east. Pisces is concealed by the glare of the sun.

15. Sun Serpens Pisces Orion Leo Position of Earth in June In June, Serpens is overhead at midnight. Leo is setting on the western horizon and Pisces is rising in the east. Orion is out of sight.

16. Sun Serpens Pisces Orion Leo Position of Earth in December Position of Earth in September Position of Earth in June Position of Earth in March In September, Pisces is overhead at midnight. Serpens is setting on the western horizon and Orion is rising in the east. Leo cannot be seen.

17. During the entire year, the Earth rotates once around the sun in a counterclockwise direction. The entire sky appears to rotate round the Earth once in that period of time.