Some of the earliest records of astronomy come out of China. There are legends that say observatories were built in China as long as 4,000 years ago. There is no doubt that mankind has been observing the stars since the beginning of manking. But the Chinese first made an art and science of it.
As many other cultures that flourished on the earth thousands of years ago the chinese predominantly viewed the stars and the heavens as an astrological pursuit. They believed that the motions of the universe had an effect on the earth and on people. This belief spurred them to make very careful observations of the sky and the objects in it. Chinese emperors always had a team of astrologists that would carefully observe the skies and make predictions. These predictions could influence many things in the lives of the chinese like when to plant, when to build or even when to start a military campaign.
This art of astrology is of course very different than the science of astronomy but it was this art of observing and predicting the motions of celestial bodies that made the chinese amazing astronomers.
Going back over 2,500 years the chinese were building observatories, and cataloging stars into maps and arrangements of constellations. The star map shown below dates back to the Song Dynasty. It was created by Su Song who was a chinest scientist. This map was first published in 1092.
The ancient chinese also used instruments that look a lot like telescopes. These were sighting tubes and simply tubes that you could look through. They were somewhat effective in that they blocked out light around a viewer allowing them to see fainer objects and to better concentrate on a single object.
The Chinese also used the moon as an accurate way to measure a year. Their calendar was broken down into twelve lunar months. And each of their lunar months was 29.53 days long wich is very accurate because we now have measured the lunar month to be 29.530879 days long.
Observations of changes in the night sky
We tend to think of the night sky as a static environment. A place that doesn't change much. But this isn't true. There are changes that occur every night and there are also changes that occur only one every hundred years or so. The chinese were very interested in these changes and very astute at finding and recording them. Here are some examples of observations they made.
Sunspots: You know about sunspots and so did the ancient chinese. Although they believed they were shadows caused by birds. They knew that it was dangerous to look directly at the sun so they observed it through pieces of translucent rock crystal or translucent jade.
Supernova: Every one hundred years or so a supernova goes off in our area of the universe. This causes it to be come much brighter than normal and sometimes this supernova star can even be seen during the day. In 1054 Chinese observers noted a supernova that was as bright as the planet venus. It could also been seen during the day. The remnant of this supernova is what we now know as the Crab nebula.
The first sighting of Halley's Comet - In modern times this is a very famous comet because it was the first instance of the path and appearance of comet being accurately predicted. Halley predicted it returns every 76 years. The ancient chinese first noted it about 2, 200 years ago. It made it's last appearance in 1986.
Modern day astronomy owes a large debt to the amazing and meticulous work that the ancient chinese did. They had cataloged the night sky and observed it for centuries.