[VIEWPOINT]A tower to observe the stars

Cheomseongdae has no doors. Nor is there record of star-gazing at the place. So one could question whether it is an astronomical observatory. Understandably, there are arguments for its being an altar rather than an observatory.
To understand Cheomseongdae, we first have to understand observatories of the past. An observatory was a place to view and record astronomical phenomena, such as the appearance of comets, the location of the moon and planets, meteors, and supernovas. But such work didn’t require special facilities because observation was possible anywhere in an open area. Therefore, an observatory was not particularly necessary.
Under such conditions, the observer might not watch on a very cold or hot day or because of personal matters. The king, then, had to receive reports about the occurrence of celestial phenomena from a local official, not from the royal observer. “Goryeo History” actually affirms such a record. A system was perhaps needed to ensure that the observer would watch the sky every day without fail. This may be how Cheomseongdae came to be built.
Here also lies the reason why Cheomseongdae has no doors. Because there were no doors, the observer had to climb up to the top using a ladder. On the top there is a place to sit, albeit not a spacious one. The observer could not help but observe the stars all night until someone returned with a ladder again. Because the observer sat in a high spot, passers-by could easily see if he was watching. From the modern viewpoint, this method may not sound good, but Cheomseongdae obtained great results. The proof is that the number of astronomical records after the establishment of Cheomseongdae was five times more than before. The records of celestial phenomena were also more specific than they were previously.
Its similarity to Gwancheondae, an observatory of the Joseon Dynasty, also proves that Cheomseongdae was an observatory. Both are similar in size and height. Gwancheondae was probably a variation of Cheomseongdae. Another similarity is their closeness to the palace. Gwancheondae is 1.2 kilometers away from Gyeongbok Palace, and Cheomseongdae is 2 kilometers away from the assumed palace site of the Silla Dynasty. They were close to the palace so that the observer could report to the king immediately when an important astronomical phenomenon occurred.
“Samguk Yusa,” or “The Memora-bilia of the Three Kingdoms,” the first record of Cheomseongdae, says, “Cheomseongdae was built with cut stones during [the reign of] Queen Seondeok.” What is important here is that its name meant “a building to observe stars.” Cheomseongdae is certainly an observatory because the early observatory of the Goryeo Dynasty was also called Cheomseongdae.
The fact that Cheomseongdae was not an altar can also be confirmed in “Samguk Sagi,” or “The Historical Records of the Three Kingdoms.” According to the book, Silla performed sacrificial rites to the sun and the moon in Bonpiyuchon, and to the stars on the south of Youngjosa. In other words, the fact that religious services were conducted in places other than Cheomseongdae proves that Cheomseongdae was not an altar.
Notable is the fact that most world-famous observatories were built during their country’s revival period. Some examples are Britain’s Greenwich Observatory, France’s Meudon Observatory and Germany’s Berlin Observatory. The Joseon Dynasty built Gwancheondae during King Sejong’s reign, when the country was the most prosperous, and Silla built Cheomseongdae during Queen Seondeok’s reign, when the country was thriving. Regrettably, Kim Bu-sik, the author of Samgu Sagi and a model of misogyny, omitted the queen’s achievement. In this sense, Iryon, the author of Samgul Yusa, seems to be more outstanding.

* The writer is the director and chief researcher of the Astronomical Information Research Group at Korea Astronomy Observatory. Translation by the JoongAng Daily staff.

by Kim Bong-gyu