Does the poet Du Fu know astronomical phenomena?

Ginseng (now called Orion) and Shang (now called Scorpio) refer to two constellations. Ginseng is in the west and business is in the east. One rises and the other sinks, so they won't meet.

The division of constellations originally came from ancient times. Ancient China, ancient Greece, ancient Babylon and ancient Egypt all had their own understanding and division of constellations. Maybe the landlord still doesn't understand what a constellation is. Constellation is a whole connected by several stars in ancient daydreams. Just as we look up at the starry sky, we will find that these stars are connected like lions and those are like swans. The ancients unified the division of star groups and became constellations. Therefore, the constellation was born very early, because people can see the sky as soon as they look up, and there will be associations. It's not like a nebula or anything You must observe through a telescope.

2. How many years the starlight reaches the earth depends on how far away we are from the earth and how many light years we need, so we look up at the starry sky. The light of every star is the light of the past, and the past is still different. Maybe this one is hundreds of years ago, and the other one is tens of thousands of years ago. Even the sunshine a few minutes ago was beautiful.