Introduction to "Astronomical Map": "Astronomical Map", authored by Huang Sang, is 2 meters long, 1.05 meters wide and 30 centimeters thick. It is the oldest ancient engraved oriental star mapping map in the world. With the North Pole as the center, the limit that can be seen in the south at 35 degrees north latitude is the outer great circle, the limit that can be seen all year round near the North Pole is the inner small circle, the equator is the middle circle, and there is a middle circle that is the ecliptic, which intersects obliquely with the equator at 24 degrees. Twenty-eight meridians of varying widths radiate from the North Pole to all directions, forming the equatorial position where the twenty-eight constellations are located. There are 1,443 stars in the picture. At that time, they were all observed with the naked eye. Today, detection with scientific instruments is 100% accurate. The text description below the picture records the astronomical knowledge of people before the Southern Song Dynasty, including the scientific explanation of the causes of solar and lunar eclipses.