Japanese scholars' selected translations of Chinese historical treatises (Volume 10) Science and Technology

Author: Liu Junwen (Editor-in-Chief), Du Shiran, Wei Xiaoming, et al. (Translators)
Publisher:
Publishing Date: 1993-08-01
Features:
Fragment: Jia Kui said: "Earlier, I submitted Fu An and others for using the ecliptic to measure the positions of the sun and moon, and their measurements were mostly accurate. However, the court historians consistently used the equator to measure, which did not align with the sun and moon. As a result, when measuring the positions of the sun and moon today, the discrepancy exceeds one degree, and they often report it as a variation. Although it is unclear what era Fu An lived in, the "Continuation of the Book of Han·Records of Pitch Pipe and Calendar" includes Jia Kui's discussion on calendars, which is generally believed to have been written around the fourth year of the Yongyuan era. Therefore, it can be considered that by the fifteenth year of the Yongyuan era, instruments similar to the ecliptic bronze instrument already existed.
Facing Fu An's measurements of the ecliptic, as mentioned in the above quote, it seems that government officials specializing in observations, such as court historians, did not yet have instruments capable of measuring the ecliptic positions. The "Ecliptic Bronze Instrument" specially referred to in the fifteenth year of the Yongyuan era is worth noting. Therefore, it can be inferred that before the fifteenth year of the Yongyuan era, in addition to court historians, there were already armillary spheres equipped with ecliptic rings in the world. In China, new astronomical observations and research were often carried out by non-specialized officials outside the court historians, and the above is one such example. Jia Kui's discussion on calendars mentions Fu An, but it remains unclear whether armillary spheres with ecliptic rings existed before Fu An.
Before the Former Han Dynasty, this can be set aside for now. According to legend, the Han Dynasty used armillary spheres during the reign of Emperor Wu with Luoxia Hong and during the reign of Emperor Xuan with Geng Shouchang. The "Records of Pitch Pipe and Calendar" in the "Records of the Grand Historian" and the "Records of Pitch Pipe and Calendar" in the "Book of Han" only mention Luoxia Hong as "calculating the calendar," without clear records of him using an armillary sphere.
In the "Discourses of Yang Xiong" written by Yang Xiong at the end of the Former Han Dynasty, it is recorded: "Someone asked about the (Huantian) theory: 'Luoxia Hong designed it, Xianyu Wangren measured it, and Geng Zhongcheng modeled it.'" Another text, the "Records of Astronomy" in the "Book of Jin," which accepted this view, states in the "Instrumental Records" section: "During the Taichu era of the Han Dynasty, Luoxia Hong, Xianyu Wangren, and Geng Shouchang created armillary spheres to examine the calendar." Later, during the reign of Emperor He, Jia Kui further refined them and added an ecliptic ring.
As mentioned earlier, there are several ambiguities regarding the ecliptic bronze instrument created by Jia Kui. In the above quote from the "Book of Jin," the instruments created by Luoxia Hong, Xianyu Wangren, and Geng Shouchang are referred to as "" (Yuan Yi), where "" (Yuan) is the same as "" (yuan, meaning round), and can be understood as armillary spheres. However, in the above quote, all three are presented as figures during the Taichu calendar reform, whereas in reality, only Luoxia Hong actively participated in the reform. After the reform, until the third year of the Yuanfeng era (78 BC), someone opposed the new calendar. To clarify the issue, the chief calendar official Xianyu Wangren and others conducted observations, while the armillary sphere is believed to have been created by Geng Shouchang in the second year of the Ganlu era (52 BC).
The "Continuation of the Book of Han·Records of Pitch Pipe and Calendar" records: "According to the second year of the Ganlu era, Geng Shouchang, the Zhongcheng of the Grand Minister, submitted a report on using the diagrammatic instrument to measure the paths of the sun and moon, examining the state of the celestial movement. The sun passed one degree past Taurus and the moon moved fifteen degrees to the east. The sun moved one degree past the Pleiades and the moon moved thirteen degrees to the east, as is known by all under the heavens. This was common knowledge before this time." In the "Records of Astronomy" in the "Book of Jin," the "" (Yuan Yi) is now referred to as the "diagrammatic instrument." Even if the "diagrammatic instrument" is also interpreted as an armillary sphere, it remains unclear whether it was equipped with an ecliptic ring.
In the above quote, if everything up to "the moon moved thirteen degrees" is what Geng Shouchang said, then it can be said that his measurements were based solely on the equator. As for the era of Luoxia Hong and Xianyu Wangren, there is no definitive evidence to confirm the existence of an ecliptic ring.
The above-mentioned "Continuation of the Book of Han·Records of Pitch Pipe and Calendar" includes the "Shi Family Star Catalogue," which states: "The ecliptic circle initially aligns with the twenty degrees of the Dipper, twenty-five degrees from the celestial pole, and twenty-one degrees from the equator." Alongside the equatorial values, it also provides the ecliptic values for the winter solstice sun's position. The winter solstice sun's position on the equator is twenty-one degrees of the Dipper, which corresponds to around 70 BC. This value is then converted into the corresponding ecliptic value.