In the times of ancient Egypt and Greece, the early astronomers didn't have binoculars or telescopes. Yet the astronomers those days gathered the information and pieced together the theories that we now refer too. How did they do this? They would go outside of their huts at night and observe the heavens. They would then repeatedly go out day after day at the same time and chart any differences or similarities they saw. Over a long period of time this produced outstanding results. One of the major things that these ancient astronomers noticed was that the stars looked a little bit like animals and other items if you connected the dots. So of course they decided to name them, and thus was the origin of the constellations. There are many different constellations, most are named after gods and animals or other general items, and each one has its very own story. That's how the ancient people amused themselves, they didn't have TV's or computers, they only had the stars, Stars that told stories about the "Great Bear-, "Orion The Hunter- or "Taurus The Bull-. The constellations were also an important tool the ancient people used like a calendar. They noticed that there were 12 major "constellations- that went throughout the sky and then repeated themselves. They noticed that it took approximately 30 days for an entire constellation to pass throughout the sky. The reason this is, is because of the apparent path that the sun takes among the stars is called the Ecliptic. While the sun is moving along the Ecliptic it passes threw the 12 constellations and this is what created the Zodiac. .
There were many different views on what the Earth's significance to the universe was and how it worked along with the sun. In 2000 B.C the ancient Egyptians thought that the Sun was a boat that sailed across the sky by the god Ra. It wasn't until about 400 B.C that this hypothesis was proven wrong.