검색
검색팝업 닫기
목록보기
Scenario

“Our History Net” has uploaded 7 new photos.

Did you see the total lunar eclipse last night?
It was my first time seeing a blood moon. If I make a wish, do you think it’ll come true?
Up until the Joseon Dynasty, a lunar eclipse was considered a bad omen.
I wonder what that huge fan of astronomy, King Sejong, thought about lunar eclipses. Hmm~ Now I’m curious~

Why did King Sejong order the advancement of astronomy?

Sejong, the 4th king of Joseon, who in the 15th century brought the dynasty up to international standards in the sciences.

King Sejong first began developing astronomical instruments and made arduous efforts to develop astronomy by installing astronomical instruments in Gyeongbokgung Palace.

With orders from King Sejong, Joseon scientists studied Chinese astronomical devices and the science behind them, and then created entirely new astronomical instruments based on the skies and natural environment of Joseon Korea and its region.

The most typical representation of this is the Angu-ilgu, a clock known as the clock of the people. Its Korean name Angbu-ilgu means a sundial whose shape resembles a bowl looking up to the sun.
Why was this sundial designed differently than flat sundials by having a concave bowl?

On a flat sundial, the length of shadows cast onto the sundial would differ according to the time, making time measurements irregular.
But the Angbu-ilgu had numbers written on a concave bowl, making reading time easier and more precise.

The Angbu-ilgu was composed of a pointed gnomon and a round, concave semi-circular bowl with several marked parallels indicating the seasons and hours.
This clock allowed one to determine both the current time and seasonal division (of 24 such divisions) at any given moment with great precision, based on where the gnomon’s shadow fell.

But, Sejong wanted to improve upon this design, to create a clock that was readable not just during the day, but also at night, and not only when it was sunny, but even when it was rainy or snowy. He wanted an automatic water clock.

Responding to this, the great scientist Jang Yeong-sil developed the Jagyeongnu to fulfill the king’s wishes. Water would fall at a set rate, with marks in the basin displaying the time based on the water level. Every hour, a copper ball would roll down and turn a lever, which would strike a bell or drum to let people know the time. This was the most technologically advanced and cutting-edge invention of the15th century in Korea.

Why was Sejong so set on having the most accurate time?
Because he wanted his rule to be orderly and without confusion.
There was a need for keeping to a schedule in such instances as the changing of the palace guard and the daily opening and closing of the city gates.

Another important reason for precise timekeeping was agriculture. The people needed to plant seeds and harvest crops at very specific times. It was also important in regards to national security. One of the first places Sejong sent one of the clocks he had made was to military forces protecting the frontier.

King Sejong built the Heumgyeonggak on the west side of Gyeongbokgung Palace’s Cheonchujeon, a building where he installed the Ongnu, a water clock that is a combination water clock and astronomical clock.
In the center of the Heumgyeonggak, a mountain made out of paper maché was erected, decorated with paintings of agricultural scenes and the four seasons.
Sejong frequently visited this place to better understand the troubles his people faced beyond the palace walls and to make legislature to benefit them.

Sejong worked to complete his studies in astronomy, as he felt the most important aspects of kingship were to care for the people and agriculture.

Sejong Perfects Joseon’s Calendar

Lee Cheonbong, a Joseon technician, reset the time by moving it up one mark (15 minutes) after he had observed the eclipse, and as a result of this, he was flogged.

- “The Annals of King Sejong”, January 1st, 1422 (Year 4 of King Sejong of Joseon)

In ancient times, the government collected information regarding dates and seasons, and used this information to govern the country in a stable manner.
Therefore, any changes in the sky were studied, and the making of the calendar as we know it today was considered an extremely important task.

Until the beginning of the Joseon dynasty, Korea used calendars straight from China.
This caused confusion with many Korean astronomers because the calendars from China did not fit Korea's latitude.
On the old calendars, auspicious and inauspicious days were recorded, but they differed from calendar to calendar, and even the timing of these events seemed incorrect.

The Joseon Ceremonies Committee suggested in a written proposition that all funerals be postponed to the following month or should be performed within three months of the passing of a person, and King Sejong accepted it.

- “The Annals of King Taejong” June 1st,1417 (Year 17 of King Taejong of Joseon)

And so, in one instance, in an effort to avoid holding a funeral service on an inauspicious day, one family held off their parents’ funeral for 10 years. As a result, King Taejong declared that members of the Yangban class (or the upper class) must hold a funeral ceremony within 3 months of the person’s passing.

Sejong felt that all auspicious and inauspicious days needed to be combined in one calendar to avoid creating confusion among his people.
Thus, the “Chiljeongsan” was born – a calendar in harmony with the skies over the Korean Peninsula.
Beginning with the position of the sun and the moon, the “Chiljeongsan” would then calculate and forecast the positions of the five planets.

In the beginning, King Sejong asked his scholars to study the Ta-tung calendar, familiarize themselves with its principles, and then apply those principles to the formulation of a calendar that would fit Korea. This was the method for creating the “Chiljeongsan Naepyeon” (or Inner Chapters to the Calculations of the Motions of the Seven Celestial Bodies)

Following this, King Sejong had his scholars create another calendar called the “Chiljeongsan Oepyeon,” which was based on the Arabic calendar, considered at the time to be the newest calendar available, but altered to match Korea and its conditions.

Following this, King Sejong had his scholars create another calendar called the “Chiljeongsan Oepyeon,” which was based on the Arabic calendar, considered at the time to be the newest calendar available, but altered to match Korea and its conditions.

Following the completion of the “Chiljeongsan,” solar eclipses, lunar eclipses, the times of sunrises and sunsets, and so forth were all set with Hanyang (Seoul) as the base standard.
Every year, an almanac would be issued in accordance with that calendar and distributed.

In the early days of the Joseon Dynasty, the almanac went from sales of just 10,000 copies to over 300,000, making it a bestseller of its day. It was known for having a positive influence on the people as it helped guide them in their daily lives.

[Epilogue]
Must-Know Facts on Culture and Art in Korean History

1. During King Sejong’s reign, the Angbu-ilgu was a sundial that allowed viewers to accurately determine the time and season.
2. Jang Yeongsil was the inventor of the automatic water clock called the Jagyeongnu.
3. A calendar is a method for determining the date and season by checking the predetermined positions of celestial bodies.

Astronomical Instruments and Calendars During King Sejong’s Reign
자료정보
페이지 상단으로 이동하기