Appendix II. Eclipses in the Reign of Emperor Chao

i. HS 7: 3b reads, in the period Shih-Yüan, "the third year, . . . . xi, (the eleventh month), on [the day] jen-ch'en, the first day of the month, there was an eclipse of the sun." (Han-chi 16: 2a agrees.) HS 27 Cb: 14b adds, "It was 9 degrees in [the constellation] Tou."

P. Hoang lists this date as Dec. 3, 84 B.C.; Oppolzer calculates his solar eclipse no. 2674 for that date. The principal star of Tou, φ Sagittarii, was then in R.A. 249°. According to my computation by Neugebauer's method, the sun was in long. 249° = 247° R.A. Oppolzer charts the path of totality as passing through Indo-China; at Ch'ang-an the eclipse reached a magnitude of 0.66 (sun's diameter = 1.00) at 11:25 a.m., local time.

In the five years between this and the last recorded eclipse in the reign of Emperor Wu, no eclipses were visible in China.

ii. HS 7: 6a reads, in the period Yüan-feng, the first year, "vii, on yi-hai, the last day, there was an eclipse of the sun, and it was total." (Han-chi 16: 6a agrees.) HS 27 Cb: 14b writes the day as "chi-hai" and adds, "It was almost total. It was 12 degrees in Chang. Liu Hsiang said, `Because it was chi-hai it was total. The significance of [this combination] is great.' " Meng K'ang (ca. 180-260) comments, "Chi is earth and hai is water. It was the pure [element of] yin, hence the eclipse was extremely great. When a solar eclipse is complete, it is [called] chi 既."

The comments of Liu Hsiang and Meng K'ang fix the day as chi-hai, not yi-hai as in the text of the "Annals" and the Han-chi. The latter's concurrence shows moreover that this error was ancient. yi-hai was furthermore neither the last day of the month nor the day of the eclipse, according to P. Hoang's calendar.

P. Hoang equates this date with Sept. 20, 80 B.C.; Oppolzer calculates his solar eclipse no. 2684 for that date. The stars of Chang, κ, ν, λ², μ, φ³ and Hydrae were then in 120°, 123°, 127°, 131°, and 135° respectively. The sun's longitude was 174° = 175° R.A. This discrepancy of longitude is hard to account for. Calculation shows that at Ch'ang-an, the eclipse reached only a magnitude of 0.77, which was at 12:53 p.m. local time. Calculation of the path of totality shows that it passed through Lake Baikal, east of Urga, and that at the present Peking the eclipse was total at 1:39 p.m. local time.

In the 4 years between this and the preceding recorded eclipse, 2 solar eclipses were visible in China; on May 18, 82 B.C. and May 6, 81 B.C. (the latter was invisible at Ch'ang-an, but calculation shows that at the present Peiping it reached a magnitude of 0.47 at 5:03 a.m., shortly after sunrise).