The inscription of Cheonsang Yeolcha Bunyajido (天象列次分野之圖) has the sun’s locations at the equinoxes, which must have been copied from the astronomical treatises in Chinese historical annals, Songshu (宋書) and Jinshu (晉書). According to the treatises, an astronomer Wang Fan (王蕃, 228–266 CE) referred those values from a calendrical system called Qianxiangli (乾象 曆, 223 CE), from which it is confirmed that it adopted the sun’s location at the winter solstice of the (211 4 )th du of the 8th lunar lodge Dou (斗) as the reference direction for equatorial lodge angles. This indicates that the sun’s locations at equinoxes and solstices in the calendrical system are the same as those in Jingchuli (景初曆, 237 CE). Hence, we propose that the sun’s location at the autumnal equinox in Cheonsang Yeolcha Bunyajido should be corrected from ‘wu du shao ruo’ (五度少弱), meaning the (51 6 )th du, to ‘wu du ruo’ (五度弱), meaning the (411 12 )th du, of the first lunar lodge Jiao (角), as seen in Jingchuli. We reconstruct the polar coordinate system used in circular star charts, assuming that the mean motion rule was applied and its reference direction was the sun’s location at the winter solstice. Considering the precession, we determined the observational epoch of the sun’s location at the winter solstice to be 𝑡o = −18.3 ± 43.0 adopting the observational error of the so-called archaic determinatives (古度). It is noteworthy that the sun’s locations at equinoxes inscribed in Cheonsang Yeolcha Bunyajido originated from Houhan Sifenli (後漢四分曆) of the Latter Han dynasty (85 CE), while the coordinate origin in the star chart is related to Taichuli (太初 曆) of the Former Han dynasty (104 BCE).

In this study, we collected articles published in the Publication of the Korean Astronomical Society (PKAS) from 1984 to 2021, and performed quantitative analyses of their various aspects. PKAS is the journal where authors can publish research papers in Korean as well as English. It seems to have an advantage of the better accessibility to all people than other astronomy journals in English only. From 1984 to 2000, the number of articles published in PKAS has been steadily increased. From 2000, the number of published articles showed a tendency to decrease slightly every year. After 2010, the number of articles in PKAS has shown a sharp decline until now. Interestingly, in this period it is found that the topics published articles became various, in particular, many articles concerning historical astronomy began to be published. PKAS was selected as an accredited journal in 2018. This is a very positive situation, and we think the future direction of PKAS is encouraging. Considering these circumstances, the PKAS is suggested to re ect ideas of "interdisciplinary fusion" and "diversity" in publishing articles in the journal for its promising future.

Hong, Dae-Yong manufactured the Tongcheon-ui (Pan-celestial Armillary Sphere) with cooperating clock researcher Na, Kyeong-Jeok, and its craftsman An, Cheo-In, in Naju of Jeolla Province in 1760 ~ 1762. Tongcheon-ui is a kind of astronomical clock with an armillary sphere which is rotated by the force generated by a lantern clock’s weight. In our study, we examine the lantern clock model of Tongcheon-ui through its description of the articles written by Hong himself. As his description, however, did not explain the detail of the mechanical process of the lantern clock, we investigate the remains of lantern clocks in the possession of Korea University Museum and Seoul National University Museum. Comparing with the clocks of these museums, we designed the lantern clock model of Tongcheon-ui which measures 115 mm (L) × 115 mm (W) × 307 mm (H). This model has used the structure of the striking train imitated from the Korea University Museum artifact and is also regulated by a foliot escapement which is connected to a going train for timekeeping. The orientation of the rotation of the going train and the striking train of our model makes a difference with the remains of both university museums. That is, on the rotation axis of the first gear set of Tongcheon-ui’s lantern clock, the going and the striking trains take on a counterclockwise and clockwise direction, respectively. The weight of 6.4 kg makes a force driving these two trains to stick to the pulley on the twine pulling across two spike gears corresponding to the going train and the striking train. This weight below the pulley may travel down about 560 mm per day. We conclude that the mechanical system of Tongcheon-ui’s lantern clock is slightly different from the Japanese style.

To accommodate today's higher education student, fewer textbooks are printed and more are becom- ing digital. Keeping with the modern era, hybrid versions of textbooks have all end-of-chapter assess- ment content moved to digital learning systems such as MindTapTM by Cengage Learningr. In this work, we introduce new pedagogical strategies to combat academic e-cheating, specifically cheating on assessments given in online astronomy courses. The strategies we present in this work are employed in Horizons: Exploring the Universe, Hybrid, 13th Edition, and Universe, Hybrid, 8th Edition, by Seeds, Backman, and Montgomery.

We present an analysis of the papers published in the journals Nature and Science in the years from 2006 to 2010. During this period, 7788 papers in total were published in the two journals. This includes 544 astronomy papers that correspond to 7.0% of the papers in 'all' research fields and 18.9% of those in the field of 'physical sciences'. The sub-fields of research of the astronomy papers are distributed, in a descending order of the number of papers, in Solar System, stellar astronomy, galaxies and the universe, the Milky Way Galaxy, and exoplanets. The observational facilities used for the studies are mainly ground-based telescopes (31.1%), spacecrafts (27.0%), and space telescopes (22.8%), while 16.0% of papers did not use any noticeable facilities and 1.7% used other facilities. Korean scientists have published 86 papers (33 in Nature and 53 in Science), which is 1.10% of all the papers (N = 7788) in the two journals. The share of papers by Korean astronomers among the scientific papers by Koreans is 8.14%, slightly higher than the contribution of astronomy papers (7.0%) in both journals.