We cannot know for certain when humans first began to carefully observe objects in the sky, but it is highly likely that it was important from prehistoric times to understand the environment around them.
If you were living many thousands of years ago, you would have been aware of the passage of the Sun and Moon across the sky.
Also the apparent rotation of the star constellations in their fixed patterns, together with those strange objects (planets Venus, Mars, Jupiter and Saturn) that looked like stars to the naked eye, but seemed to wander between the fixed stars in an odd way.
Practical uses of astronomy would have been obvious from the earliest primeval times.
Understanding the signs in the sky which foretold the changes of seasons, would have been vital for planting of crops and the raising of animals. If you were a sailor at sea, knowledge of how to use the stars for navigation, would have been similarly important.
Throughout the ancient world there is evidence that people studied the sky.
All the early civilisations, such as those in Egypt, Greece and China, had names for the brightest stars, together with their groupings and patterns. Associations, stories and legends grew up about these constellations. These stories and legends continue to this day of course, not as astronomy, but as astrology.
Remarkable events like lunar and solar eclipses, plus the ocassional appearance of bright comets, were interpreted in times gone by as messages from the Gods and used to influence events of the day.
It is generally accepted that many prehistoric building structures had a celestial significance. Stonehenge, the ancient stone circle in Wiltshire, England is a prime example.
Debate is still going on about whether Stonehenge was primarily a sacred site for ritual and celebration, or a celestial observatory for marking the turning points of the seasons and the significant dates in the astronomical calendar.
Nevertheless, it seems likely that the location of the site and the positioning of much of the original parts of the structure, were decided upon to the satisfy requirements of early priests and astronomers.
Specifically, the four original primary markers form a rectangle that seems to mark the extreme positions of sunrise and sunset, during the year at this latitude.
The pyramids of ancient Egypt also show links and alignments with celestial events and objects. There has been much study and debate over the details, but it is clear that astronomical observation played an important part in the building plans for at least some of the pyramids.
At roughly the same time as people in ancient Britain were building Stonehenge (around 2700 BC), Eygyptian builders were creating some of the pyramids. Influenced by priest astronomers who had a preoccupaation with the movements of the Sun, Moon and stars, structures such as the Great Pyramid were being carefully aligned.
The ancient era of astronomy began to change into the modern science we now understand, with Greek scientists around 300 BC.
Aristotle and Aristarchus began to study and write down their obervations and theories, in a way that we know recognise as scientific discovery.
