The respected Comrade
"A valuable legacy created by our ancestors through their struggle and creative activities, historical sites and relics are an asset of the nation that should be handed down from one generation to the next."
Among the precious cultural heritages created by our ancestors through creative activities for improving nature and society, there is special star pictures depicted at the Koguryo tomb murals.
The star pictures of the murals of Koguryo tombs, a precious cultural heritage of the Korean nation, were drawn in conformity with the demands and interests of the ruling class at that time, but they reflect the high knowledge of the astronomy of the Koguryo people, their unique religious ideas and noble national sentiments, thus contributing to the treasure house of the world culture.
The mural with a star picture is about 20 among 100 the Koguryo mural tombs known so far.
The star pictures depicted at Koguryo tomb murals are good examples of the development of Koguryo astronomy which was highly developed at that time.
The excellence of the star picture depicted in Koguryo tomb murals is well manifested, above all, in its rich content.
The mural paintings of Koguryo tombs begin to be drawn in azimuth by the characteristic constellations such as The Plough in the second to third centuries, and in the fourth century, they become richer in content with the increase in the number of constellations. In the sixth century, five planets and 28 constellations are drawn as in the mural tombs of Tokhung-ri, Tokhwa-ri Tomb No.2 and Ryongsanri Tomb No. 1, and the contents of the star paintings are enriched.
* Twenty-eight numbers represent the unique names of constellations that are attached to the sky, dividing the celestial body into 28.
The Tokhung mural tomb, together with the sun and the moon, depicts five planetary pictures of Mars, Mercury, Jupiter, Venus, Saturn, Earth and Galaxy, and the The Plough, Hosu, Wisu, Silsu, Myosu, Tusu, Samsu, Jasu, W-shaped constellations. In particular, W-shaped constellations which are not found at all in the astronomical chart and star pictures of other countries is the one which is called Cassiopia in modern astronomy. This locates opposite to The Plough with the North star, so in modern astronomy they find the North pole using this constellation when the The Plough goes below the horizon.
In the Tokhung-ri mural tomb, you can see the W-shaped Cassiopia. This means the Koguryo people used this constellation actively with the The Plough in finding the North Star.
The Tokhwa-ri tomb No.2 shows 15 constellations and the five constellations including Silsong, Pyoksong, Wisong, Jongsong, Ryusong, which have its own names.
And the star picture of the tomb No. 1 of Ryongsan-ri which was depicted splendidly with gold powder described 28 constellations using 136 stars.
This clearly shows a part of the astronomy of Koguryo that was highly developed that day, enriching the content of the star pictures of Koguryo.
The superiority of the star painting is also well manifested in the scientific representation of the shape and state of the stars.
Firstly, it is expressed in the fact that all individual stars are drawn in circles.
Drawing all the stars that symbolize the heaven in circles shows that the Koguryo people made a very accurate observation of the stars, because the stars glittering in the night sky look like five or six-hexagons in shape because they are scattered while passing through the atmosphere, but they are actually round-shaped.
It is also well manifested in the fact that the size and brightness degree of stars are accurately drawn.
Stars look different according to their size, brightness, and distance, and setting and recording the rank accordingly is of great significance in the search, observation and recording of stars.
The Koguryo people depicted stars in different sizes and colors, drawing pictures of stars on murals.
For example the stars of Ryongsan-ri tomb.No. 1 were drawn in six different sizes, Tokhwa-ri tomb No. 2 in three, murals of Tokhung-ri tomb in four. The colours of the stars are also depicted in red, white and blue in murals of Tokhung-ri tomb and those of Tokhwa-ri tomb No. 2 are depicted in red, white and purple, those of Jangchon tomb No. 1 and Ryongsan-ri tomb No. 1 are drawn in yellow and gold.
This means that the people of Koguryo divided the stars into six groups according to their size and also displayed their brightness in red, yellow, white, blue, etc.
* Modern astronomy also distinguishes stars into six (distinguishable by the naked eye) according to their brightness.
The Chinese star pictures at that time showed neither the size nor the brightness degree of the stars, while the star pictures of Koguryo depict the brightness degree of the stars, and this clearly shows the scientific character of the star pictures of Koguryo.
The scientific nature of the star picture is also well illustrated by the arrangement of stars based on the coordinate notation by the arctic projection method.
Koguryo people thought that all the celestial bodies are rotating regularly around the Arctic, used polar coordinates already in the making of star pictures, which shows that their astronomical knowledge was at a very high level at that time.
*Pole coordinates are the means of finding the absolute position of a star, that regards the line connecting the reference star (the α star of the maiden star) to the north pole as the baseline and measures angle at which the line connects the corresponding star to the north pole and the distance from the north to the corresponding star.
The method of finding the absolute position of a star on the basis of polar coordinates is also recognized as one of the most accurate methods in modern astronomy.
The star pictures drawn at Koguryo tomb murals are all star pictures drawn by the arctic projection method with the source of light at the south pole and the equatorial plane as the projective plane.
For example, the star pictures of the Ssirum and Dance Tomb is drawn on an octagonal ceiling and each of the prop platform is represented by a circle, with 10 concentric circles of Dance tomb and 6 of Ssirum tomb.
This star picture made the line connecting the sun which was drawn the three-legged crow on the east of the tomb ceiling as baseline and selected the location of star by measuring the angle which was made between that line and corresponding star, the distance from the center of the ceiling to the corresponding star.
The star picture of Tokhwa-ri tomb. No.2 was drawn by making the line connecting each standard star in the center of the ceiling and drawing it according to the angle of the line that connects the stars in the ceiling center.
In this tomb 28 constellations were only drawn on the second platform of octagon prop and it also used polar coordinates.
This shows that Koguryo people applied polar coordinates skillfully in painting star pictures of murals and it adds the historical value of Koguryo star paintings.
Among the 90 tombs of Wei Dynasty, Jin Dynasty and North Dynasty, South Dynasty, Sui Dynasty and Tang Dynasty of China, there are only 16 with star paintings. In addition it is difficult to find the astronomical knowledge of the people at that time, because most of star paintings show decorative character strongly that the celling of the tomb is sky. The star pictures depicted on Koguryo tomb murals clearly show the high level of development of the astronomy of Koguryo for their rich content and scientific character of description.
