Analysis of Ancient Astronomical Phenomena in Samguksagi
Yong Bok LeeSeoul National University of Education,Seoul, Korea
Abstract
There are a lot of records on astronomical phenomena in ancient
Korean Historical Books. The most oldest record as official
documentation is Samguksagi which was written Kim Bu-sik in 1174.
It is historical records of three kingdom period between 57 BC and992 AD. The records contain many astronomical phenomena andnatural disasters as well as historical events.
We selected astronomical phenomena among the records, which
are solar eclipses, comets, meteorites, movements of planets, solar
observations, nova, and atmospheric appearances. All of the records
are 240 which number of eclipses is 69, comets 49, meteorites 47,
planets 41, sun 6, stars 6, atmosphere 18, and others 4. Especiallymost of records are identified as real phenomena by computer
calculation.
We analyzed the records concerning on classification by type ofastronomical events, observing frequency for duration, comparison
with Chinese, and relation with political situation. We found thatmost of the records are correlated with many kinds of domestic
affairs and accidents. The types of events are related with king, war,revolt, natural disaster, and domestic affair.
We concluded that most of phenomena are closely related withmany events in ancient society. Therefore most of records in theancient historical book are real and correct writing.

- 1 -I. Introduction
Samguksagi(三國史記) was written by Kim Bu-sik in 1174 during
Goryeo Dynasty (918-1392 AD). The Book were compiled from themany kinds of ancient historical records those were descendent
before the time in Korea (Kim 1174). It is mainly historical records
during Three Kingdom Period (57 BC - 935 AD). Three Kingdoms areconsist of Shilla were founded in 57 BC to 918 AD), Goguryeo from37 BC to 668 AD), and Baekje from 18 BC to 660 AD.
The book contains 50 volumes and was separated into four parts.
First part as main history is consists of 28 volumes, the second isrituals and topography of 9, third is the table of chronicle of 3, andthe fourth is the series of biographies of 10. Especially it contains
240

astronomical

phenomena

amongthehistoricaleventsandaccidents.
For our research, we selected the records in the volumes in details
and analyses the astronomical phenomena. Most of records werecalculated the records using computer programming which are realor imaginary. Among the records, eclipses, planets' motion, meteorite
showers and the Moon's positions are possible to verify the realfacts or not.

II. Classification of Astronomical Phenomena
1. Classification of astronomical phenomena
As a first procedure, we selected the astronomical phenomena
which are related on the Solar or Lunar eclipses, Comets, Meteorites,- 2 -planets, and stars among a lot of historical records. Following table
is a example for selection of records, which are appeared in themain history of Shilla, volume 1.
Table

1.

Selectionandclassification

ofastronomicalphenomena

inSamguksagi, volume 1-st.
Class

Year King's reign and contents

SE-53

赫居世四年 四月辛丑朔 日有食之

CO

-48

赫居世九年 春三月 有星孛于王良CO-43

赫居世十四年 夏四月 有星孛于參SE-33

赫居世二十四年 夏六月壬申晦 日有食之SE-27

赫居世三十年 夏四月己亥晦 日有食之SE-25

赫居世三十二年 秋八月乙卯晦 日有食之SE-14

赫居世四十三年 春二月乙酉晦 日有食之CO- 3

赫居世五十四年 春二月乙酉 星孛于河鼓SE- 1

赫居世五十六年 春五月申丑朔 日有食之SE2赫居世五十九年 秋九月戊申晦 日有食之SE

6

南海 三年 冬十月丙辰朔 日有食之ME

14

南海 十一年 樂浪謂內虛 來攻金城甚急 夜有流星 墜於賊營SE16

南海 十三年 秋七月戊子晦 日有食之PL

23

南海 二十年 秋 太白入太微CO54

儒理 三十一年 春二月 星孛于紫宮

CO59

脫解 三年 六月 有星孛于天船CO79

脫解 二十三年 春二月 慧星見東方 又見北方 二十日乃滅

Symbol of class are following
SE: Solar eclipse, CO: Comet, ME: Meteorite, PL: Planet, ST: StarWe searched and read the contents and sentences carefully one byone. We selected subjects those are connected with astronomical
phenomena among the records in Samguksagi. We classified theminto the eight kinds of classes concerning on the astronomical events- 3 -and decided frequencies of the event.
Table 2. Number of observations in each type
Phenomena

No. of obs.

Eclipses69

Comets49

Meteorites and showers

47

Planets' movements

41

Sun’s activities

5Stars6

Atmospheric phenomena

18

The others

4

Total

240

Table 2 shows the kinds of astronomical phenomena and numberof observed records in the Samguksagi. The type of phenomena arefollowing in the order of frequency which are eclipses, comets,
meteorites, planet's motions and so on. The order of frequency
means the important appearance of the phenomena. As we know, thesolar eclipses among the records are the most important event inthe sky.
2. Counting the number of observations
We classified in each type that were recorded in each kingdoms.
Fig. 1 shows the recorded number of phenomena in each kingdoms.
The

total number of observations in each kingdom are following.

The kingdom of Shilla is 146 observations as 60.8%, Goguryeo 34
observations as 14.2%, and Baekje 60 observations as 25.0%. Shilla- 4 -made the most of observations had been recorded for 992 years,Goguryeo for 705 years, and Baekje for 678 years. Most of historical
records had been kept by Unified Shilla, and some of them were lostor destructed. The records on eclipses, comets, and meteorites aredominant phenomena as portion of 69%.

Fig. 1. Astronomical records number of each kingdoms in Samguksagi.

Fig. 1 shows the number of observed records in each astronomical
phenomena andin each kingdoms. The records of Shilla are more

dominant than the other kingdoms. It would be caused by long
duration for observations and the records were compiled by Shilla.
3. Characteristics of each types
The type of the phenomena can be classified which shows in Table
3. Eclipses separated into solar and lunar. Meteorites are divided into

- 5 -shooting stars, meteor showers, and normal meteorite. In the case ofplanets' motion, it is classified five characteristics. First case is that
the Moon is close to stars or occults stars in the sky. Second caseis that the Moon is close to planets or occults them in the sky.
Thirdcaseisthattheplanets

areclosetostars

orspecialconstellations.
Table 3. Types of phenomena and its classification
TypeClassification

Eclipseso Solar eclipses
o Lunar eclipses

Cometso Cometso Shooting stars

Meteoriteso Meteo showers
o Meteoriteso Moon's approach to stars
o Moon's approach to planets

Planet's movemento Planets' approach to stars
o Planets' approach to each other
o Venus can be seen in day timeo White rainbow by the Sun

Sun's activities

o Solar glowo Sun’s ears by solar activity

Stars

The otherso Supernova
o Appearance of Canopus
o White or red glow in the airo Unique atmospheric phenomena

Fourth is that the planets are close to each others or occulted byeach other. Fifth is that Venus was seen in day time, which is- 6 -unique phenomena. It is believed that the most of phenomena arerelated to the omen on domestic affair or nature's disasters.
The others are related to solar activity which are white rainbow by
the Sun, solar glow, and appearance of the Sun’s ears by solar
activities. Most of them have close relation to solar activities like assunspot, flare and prominence. As a rare phenomena, supernova andCanopus were observed. The Canopus almost can be observed at
capital of Goryeo Dynasty. Only it is possible to observe at thesouthern seaside area in Korea, because of its low declination.

III. Analysis of the phenomena
1. Comparison with Chinese records
All of the observed records in Samguksagi were compared withChinese using the List of Ancient Astronomical Records (江蘇科學技術出版社 1988). We compared all of records in Samguksagi with ancient
Chinese. Among the records, most of eclipses are almost coincident
with Chinese, that the ratio is almost 94%. It means that most ofeclipse data in Samguksagi are compared with Chinese when it wascompiled.
However, coincident rate with Chinese of another type records are
below 40% that is relatively low rate. The result means that most ofrecords in Samguksagi would be independent observed records
during the period of three kingdom. It is not referred or copied datafrom Chinese records.

- 7 -Table 4. Comparison with Chinese records
Obs. No,in Samguksagi

Compared withChinese RecordsRatio(%)

Eclipses

6963

94.0

Comets4924

36.7

Meteorites

473

12.5Planets

4100.0

Sun

500.0

Stars

6240.0Atmosphere1800.0

Others4Type

Especiallytherecords

ontheplanets'movement

andSun'sactivities are almost found in the Chinese. Such facts show clearly
evidence that records in Samguksagi are independent records.
2. Characteristics of observations
Most

dominant

recordsareon

thesolareclipses,which

isconnected with king’s misfortune in domestic affairs. When the solar
eclipses appear in the sky, special ritual performs nationwide toavoid from the unexpected calamity. The ceremony was leaded byking.
It is believed that appearance of comet shows a omen for war,invasion, or rebellion in domestic or from foreign. It is a kind ofsubjects on fear. Meteorites mean death of king, high official,general, or defeat in war.
Position and movement of planets in constellation happen various
accidents and expect misfortune in the country. Records on eclipses,- 8 -comets, and meteorites have main portion for all astronomical
observations. Therefore those phenomena have important meaning
during ancient times.
3. Verification of records as real events
Following the three of kinds of phenomena can be confirmed orverified by computer logics① Solar and lunar eclipses② Shooting showers③ Planets’ movement

Fig. 2. First record of solar eclipse 54 BC in Samguksagi

Records of shooting showers and meteo showers in Samguksagi- 9 -have been already studied by several researchers Yang et. al. 2004,Parkenier, et. al. 2000). Already we conformed the solar eclipses
during the period of three kingdom by computer calculation, which
are real records or not (Lee, et al. 2005).
The book shows the table for solar eclipses, solar eclipse map,
catalogue of solar eclipse during three kingdom period from BC57 till
AD935. Now we research reality on another phenomena using thecomputer calculations which are real events, or not.
Most of solar eclipses were recorded almost as real events. We have
proved 53 among 67 records as real eclipses by computer code. The
first solar eclipse records in Samguksagi was appeared on the 9th ofMay in 54 BC in solar Julian calendar as in Fig, 2. The solar eclipse
was proceed for 6 minutes and the magnitude was 0.74 by thecalculation.
The records on the Venus were already verified by computer
programming, which Venus was seen in daytime (Park 2002). Amongthe six records, the four were calculated. The Venus, one of inferior
planets is getting brighten from the position of superior conjunction
to interior conjunction. The brightness of the Venus vary in Fig. 3.
On the peak brightness of the Venus can be seen even in day time.
Calculated records of the Venus in Samguksagi are following which
are not appeared in Chinese.
① Main History of Baekje, Winter October in King Gusu 11-year(AD 224), the Venus appeared in the sky during day time.
( 百濟本紀 仇首王十一年 冬十月 太白晝見 )② Main History of Baekje, Autumn July in King Ashin 3-year (AD555), the Venus appeared in the sky during day time.

- 10 -( 百濟本紀 阿莘王三年 秋七月 太白晝見 )③ Main History of Goguryeo, November in King Yangwon 10-year(AD 394), the Venus appeared in the sky during day time.
( 高句麗本紀陽原王十年 十一月 太白晝見 )④ Main History of Shilla, November in King Deokheung 2-year(AD 827), the Venus appeared in the sky during day time
( 新羅本紀 興德王二年 秋八月 太白晝見 )Fig. 3. The brightness variation of the Venus in AD 224, AD 394, AD 555,
and AD 827 (Park 2002).

Fig. 3 shows the results calculated by computer code. The sign ofarrow means the time of observed records in Samguksagi. It isnearly coincident with peak brightness. The results are evidence that
therecords

arerealobservational

records.

However,

thefourrecords can't be found in Chinese. It means that the records are- 11 -

independent, not connected with Chinese.
4. Distribution of astronomical records
We arranged the number of records in Samguksagi with the50-year intervals. The frequency of the records within interval don't
show

uniform

distribution.

Therearetwopeaksoffrequency

apparently on the late 2nd and 7th century in Table 4. The firstpeak was appeared in the period for unstable situation among three
kingdoms and the second is unifying period by Shilla.

Fig. 4. The distribution of observed astronomical records in the interval of
50 years.

Mean value of frequency in records is nearly 12 observations withinterval of 50 years. Exceptionally 12 observations were recorded inBC which are 10 solar eclipses, 3 comets, one white glow and one- 12 -star occultation by planet. The records of 12 are consist of 9 inShilla, 2 in Goguryeo, and 1 in Baekje history. Most of records in BCarealmost

accordedwithChinese,exceptoneevent.

The

characteristic of the records could be seen in the area of Three
Kingdoms and Chinese.

III. Conclusions
Most of astronomical records would be almost real existences
which are identified by computer calculations, like as solar eclipses,
shooting showers, and planetary movements. Most of the records inSamguksagi are not coincident with Chinese. Therefore the ancientastronomical

observations

show

almostindependent

records

compared with Chinese.
A lot of astronomical records were recorded from the early threekingdomperiod.

However,manyrecords

weredisappeared

orexcluded on the compilation of the historical books. Early records
like as solar eclipses or comets before BC would be used for
decisionofchronicles

in

early

threekingdomperiod.

Suchphenomena were simultaneously appeared in three kingdoms as well
as China.

References
Kim, Busik. 1174, Samgusagi.
Lee, Y.B., Ahn, Y.S., Ihm, I.S., Kim, D.B. 2005, The Solar Eclipse
Maps During the Three Kingdom Period.

- 13 -Park, C. 2002, Our History carved in the Sky, Kimyoung Publ. Co.
Pankenier, D., Xu, Z., and Jiang, Y. 2000. Archaeoastronomy in East
Asia: Historical Observational Records of Comets and Meteor
Showers from China, Japan, and Korea, CRC Press
Yang, H.J., Park, C., and Park, M.G. 2005, Analysis of historicalmeteo and meteo shower records : Korea, China, and Japan.
Icarus, 175, 215-225.
江蘇科學技術出版社, 1988. List of Ancient Astronomical Records.

- 14 -