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Appendix IV. The Eclipses during the Reign of the Emperor Kao-Tsu
During this period of twelve (or fifteen) years, only three eclipses are recorded. We discuss them in chronological order.
i. In the third year of Kao-tsu's reign, the tenth month, on the day chia-hsü, a solar eclipse is recorded (1A: 35a). This date was, according to P. Hoang, Concordance des chronologies néoméniques, chinoise et européenne, ("Variétés sinologiques," no. 29), Shanghai, 1910, (which is used for dates throughout), December 20, 205 B.C. For that date Oppolzer calculated his solar eclipse no. 2387. It was merely partial; calculation according to the method in P. V. Neugebauer, Astronomische Chronologie (which is used for such calculations throughout), shows that the eclipse reached a magnitude of 0.51 (the diameter of the sun being 1.00) at Ch'ang-an at 10:44 a.m., local time.
HS 27 Cb: 13a adds, "It was 20 degrees in [the constellation] Tou," whose stars were then in R.A. 241.1° to 253.3°. The sun was in long. 266.0° = 265.6° R.A. 1 There is thus good agreement in both the date and location of the sun.
ii. In the third year, the eleventh month, the day kuei-mao, the last day of the month, a second solar eclipse is listed (1A: 35a). HS 27 Cb: 13a adds, "It was three degrees in [the constellation] Hsü, whose two stars, α Equulei and β Aquarii, were then in R.A. 291.1° and 293.2°. This date was Jan. 18, 204 B.C., but there was no eclipse on that date, for Oppolzer gives none.
The Han-chi (written by Hsün Yüeh, lived 148-209) records the preceding and the next eclipse (2: 11b, 4: 2a), copying the recording in the HS, but omits this one, which, in view of the fact that the Han-chi takes its material mostly from the HS, makes it look as though this eclipse was not in the text of the HS during the second century A.D. If so, it was interpolated both into chapters 1 and 27. In view of the fact that Hsün Yüeh noted all the other eclipses that are in the HS for the first half century of the Han period, even the one only found in HS ch. 27 (cf. ch. 4, App. IV, vi), it is difficult to explain otherwise his omission of this eclipse.
During the seven years between the proceeding recorded eclipse and the next one, there occurred 14 solar eclipses, of which only one was visible in China. 2 Oppolzer numbers this one 2396, and dates it on Oct. 8, 201 B.C., which was in the sixth year, eighth month, on the last day, kuei-wei (if Hoang's calendar is one day in error). Oppolzer calculates the sun in long. 191.6° = 190.7° R.A. The magnitude of this eclipse was calculated for Ch'ang-an and was found to have reached only 0.02, at 7:44 a.m. local time, so that it was practically invisible there; at the present Pei-p'ing its magnitude however reached 0.28 at 8:26 a.m., local time, so that this eclipse might have been reported from the east. Oppolzer's solar eclipse no. 2400, on Aug. 18, 199 B.C. seemed also visible in China, but calculation showed that it was invisible in any part of China and even in the present Canton.
The eclipse of 201 B.C. might have been the one intended by this recording, although it is not easy to explain the discrepancy of the cyclical day. The SC does not record any of the three eclipses that the HS lists in the reign of Kao-tsu. Pan Ku thus inserted them into the account of events given in the SC from some other source. Some astronomer who edited the list of eclipses thus used by Pan Ku might have given an illegibly dated eclipse the next possible date for an eclipse after the first and legibly dated solar eclipse. But two solar eclipses at successive new moons can happen only when two small eclipses occur in different (northern and southern) hemispheres.
Since however the Han-chi does not have this eclipse, it seems more likely that some person of the third or later centuries interpolated this eclipse for a time when he knew that an eclipse might have happened, in order to emphasize the gravity of the period. In June/July of this year, Kao-tsu barely escaped with his life from the siege of Jung-yang.
The location in the heavens given for this eclipse does not agree with anything we can calculate. It must have been calculated from the date of the year given to this eclipse, for it is about 28 Chinese degrees after the preceding one.
iii. In the ninth year, the sixth month, on the day yi-wei, the last day of the month, a third solar eclipse is recorded (1B: 14b). This date was Aug. 7, 198 B.C.; Oppolzer calculates his solar eclipse no. 2402 for that date. HS 27 Cb: 13a adds, "It was 13 degrees in [the constellation] Chang," whose stars then ranged from 118.6° to 133° R.A. Oppolzer calculates the sun as at long. 129.4° = 131.9° R.A. There is thus a very close checking between observation and calculation here.
1. Since Chinese astronomical data were always referred to the equator, not the ecliptic, celestial positions must be reduced to right ascension for purposes of comparison.
2. Besides those whose location Oppolzer charts, the following three partial eclipses were invisible because they belong to initial (i.) or terminal (t.) runs in exeligmos series whose nearest umbral eclipse was located near the south pole: no. 2389 (i.); no. 2390 (t.); and no. 2398 (t.). In addition two partial eclipses were visible in the northern hemisphere, both of which were invisible in China: (1) no. 2388, on May 17, 204 B.C.; calculation shows that this eclipse was invisible; (2) no. 2397, on Mar. 4, 200 B.C.; calculation shows that at lat. 40°N it was visible only in the Atlantic Ocean and Europe.
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|Published by The Institute for Advanced Technology in the Humanities, © Copyright 2003 by Anne Kinney and the University of Virginia|