Study on the system of night hours for decoding Korean astronomical records of 1625–1787

Lee, Ki-Won; Ahn, Young Sook; Hong, Yuan

doi:10.1016/j.asr.2011.04.002

Cited by 11 publications

(10 citation statements)

References 7 publications

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“…9, 12, etc.) show no change; this is different from the accounts in the Joseonwangjosillok (Lee et al 2012b), a representative history book of the Joseon dynasty. Moreover, those accounts do not provide a definite reference hour for the change of the observation date.…”

Section: Characteristics Of the Eclipse Accountsmentioning

confidence: 56%

“…However, because he focused on estimating a ∆T (i.e., the difference between dynamical time and universal time: TD -UT) value, the lunar eclipse accounts of the Goryeo dynasty without an observation time were not utilized. Very recently, Lee et al (2012b) studied the system of night hours using lunar eclipse accounts, but used the accounts of the Joseon dynasty in that work.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of the Lunar Eclipse Records From the Goryeosa

Lee¹,

Mihn²,

Ahn³

et al. 2016

Journal of The Korean Astronomical Society

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Abstract:In this paper, we study the lunar eclipse records in the Goryeosa (History of the Goryeo Dynasty), an official history book of the Goryeo dynasty (A.D. 918 -1392). In the history book, a total of 228 lunar eclipse accounts are recorded, covering the period from 1009 to 1392. However, we find that two accounts are duplications and four accounts correspond to no known lunar eclipses around the dates. For the remaining lunar eclipses, we calculate the magnitude and the time of the eclipse at different phases using the DE406 ephemeris. Of the 222 lunar eclipse accounts, we find that the minimum penumbral magnitude was 0.5583. For eclipses which occurred after midnight, we find that some accounts were recorded on the day before the eclipse, like the astronomical records of the Joseonwangjosillok (Annals of the Joseon Dynasty), while others were on the day of the lunar eclipse. We also find that four accounts show a difference in the Julian dates between this study and that of Ahn et al., even though it is assumed that the Goryeo court did not change the dates in the accounts for lunar eclipses that occurred after midnight. With regard to the contents of the lunar eclipse accounts, we confirm that the accounts recorded as total eclipses are accurate, except for two accounts. However, both eclipses were very close to the total eclipse. We also confirm that all predicted lunar eclipses did occur, although one eclipse happened two days after the predicted date. In conclusion, we believe that this study is very helpful for investigating the lunar eclipse accounts of other periods in Korea, and furthermore, useful for verifying the calendar dates of the Goryeo dynasty.

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Section: Characteristics Of the Eclipse Accountsmentioning

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Analysis of the Lunar Eclipse Records From the Goryeosa

Lee¹,

Mihn²,

Ahn³

et al. 2016

Journal of The Korean Astronomical Society

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“…On the other hand, the Ilgi has many records starting from August 25. Although the first record of the Sillok does not mention the observation time, according to the Ilgi, it was 5 Gyeong 3 Jeom (for the system by which the hour of the night was recorded in the Joseon Dynasty, refer to Lee et al 2011). Therefore, we can be certain that no change in date was made in the Sillok for the observations during the night, as noted by several authors.…”

Section: Halley's Comet In 1682mentioning

confidence: 90%

“…In this paper, we used the algorithms of Meeus (1998), osculating orbital elements of Yeomans & Kiang (1981), astronomical ephemerides of Bretagnon & Francou (1988), and values of ΔT (i.e., the difference between terrestrial and universal times; for details, see Lee et al 2011) from Morrison & Stephenson (2004) to compute the orbital path of Halley's comet in each return. In addition, we also calculated the solar elongation and the distance from Earth for Halley's comet appeared in 760 and 1222.…”

Section: Modern Calculationsmentioning

confidence: 99%

Korean Historical Records on Halley's Comet Revisited

Lee¹,

Mihn²,

Ahn³

2014

Journal of Astronomy and Space Sciences

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“…The sunrise and sunset times were considered to be the moments when the zenith distance of the Sun (z ⊙ ) was 90°, at least in the case of the early Joseon dynasty (Lee et al 2011). However, we used a value of z ⊙ of 90° 50′ (i.e., the modern definition) considering the apparent solar radius of 16′ and the atmospheric refraction of 34′ (Meeus 1998).…”

Section: Modern Calculationsmentioning

confidence: 99%

Daylight Observations of Venus with Naked Eye in the Goryeosa

Lee¹

2017

Journal of Astronomy and Space Sciences

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In this paper, we investigate the observations of Venus in daytime that are recorded in the Goryeosa (History of the Goryeo Dynasty, A.D. 918-1392). There are a total of 167 accounts of such observations in this historical book, spanning a period of 378 yr (from 1014 to 1392). These include six accounts where the days of the observation are not specified and two accounts where the phase angles are outside the calculation range of the equation used in our study. We analyze the number distribution of 164 accounts in 16 yr intervals covering the period from 1023 to 1391. We find that this distribution shows its minimum at around 1232, when the Goryeo dynasty moved the capital to the Ganghwa Island because of the Mongol invasion, and its maximum at around 1390, about the time when the dynasty fell. In addition, we calculate the azimuth, altitude, solar elongation, and apparent magnitude of Venus at sunset for 159 observations, excluding the eight accounts mentioned above, using the DE 406 ephemeris and modern astronomical algorithms. We find that the average elongation and magnitude of Venus on the days of those accounts were ~40° and -4.5, respectively, whereas the minimum magnitude was -3.8. The results of this study are useful for estimating the practical conditions for observing Venus in daylight with the naked eye and they also provide additional insight into the corresponding historical accounts contained in the Goryeosa.

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Study on the system of night hours for decoding Korean astronomical records of 1625–1787

Cited by 11 publications

References 7 publications

Analysis of the Lunar Eclipse Records From the Goryeosa

Analysis of the Lunar Eclipse Records From the Goryeosa

Korean Historical Records on Halley's Comet Revisited

Daylight Observations of Venus with Naked Eye in the Goryeosa

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