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卷四十二 志第十二: 曆象志上

Volume 42 Treatises 12: Celestial Phenomena 1

Chapter 42 of 遼史 · History of Liao
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Chapter 42
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1
Celestial Phenomena Treatise I
2
The Liao rose from You and Ying; as ritual and institutions matured, they issued calendars and set the new moon for over two hundred years. Ordered to compile the History of Liao on the model of the Song and Jin histories, we cannot omit the Great Brightness Calendar. Official calendrical methods were barred from circulation; in seeking the Great Brightness epoch we found Zu Chongzhi's procedures in an outside history. Did the Liao calendar ultimately derive from Chongzhi's methods? The present dynasty too once adopted them. Working forward with Chongzhi's arithmetic to the Liao calendar reform and deriving the epoch from that point yields the Liao Great Brightness Calendar. The Liao calendar could be reconstructed from this material, but we leave it unreconstructed, for histories prize deliberate gaps. An outside history records the procedures, the Directorate of Astronomy keeps the office, and this treatise in the History of Liao is enough. Hence the Calendar and Celestial Phenomena Treatise.
3
In Song Daming year 6 (462 CE) Zu Chongzhi presented the Jiazi Epoch Calendar methods; before adoption they were called the Great Brightness Calendar. From upper-origin jiazi to Song Daming year 7 (guimao) is 51,939 years beyond the epoch count. Origin factor (yuan fa): 592,365.
4
Era factor (ji fa): 39,491. Rule years (zhang sui): 391. Rule months (zhang yue): 4,836. Rule intercalations (zhang run): 144.
5
Intercalation factor (run fa): 12. Month factor (yue fa): 116,321. Day factor (ri fa): 3,939. Remainder number (yu shu): 207,044.
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Year remainder (sui yu): 9,589. Submergence parts (mo fen): 3,605,951. Submergence factor (mo fa): 51,761. Circumference of heaven (zhou tian): 14,424,664.
7
Void parts (xu fen): 10,449. Motion-part factor (xing fen fa): 23. Small-part factor (xiao fen fa): 1,717. Communication cycle (tong zhou): 726,810.
8
Conjunction cycle (hui zhou): 717,777. Communication factor (tong fa): 26,377. Difference rate (cha lu): 39. Procedure to compute new moons:
9
滿 滿
Take the years since upper origin (outside the count), multiply by rule months, divide by rule years for accumulated months; the remainder is intercalary remainder. If intercalary remainder is 247 or above, the year has a leap month. Multiply accumulated months by the month factor; divide by the day factor for accumulated days; the remainder is fractional day remainder (xiao yu). Subtract full sixty-day cycles from accumulated days; the remainder is greater remainder (da yu). Count greater remainder from jiazi (outside the count) to obtain the new moon of civil month 11 for the target year. If fractional day remainder is 1,849 or more, the month is a long month (30 days).
10
To find the next month:
11
滿滿
Add 29 to greater remainder and 2,090 to fractional day remainder. When fractional remainder fills the day factor, carry to greater remainder; when greater remainder fills sixty days, drop it and name as before for the next new moon. To find first quarter and full moon:
12
滿滿
Add 7 to new-moon greater remainder, 1,507 to small remainder, and 1 to small parts. When small parts reach 4, carry to small remainder; when small remainder fills the day factor, carry to greater remainder; name as before for first quarter. Add again for full moon, again for last quarter, and again for the following new moon. Procedure for computing intercalation:
13
滿 退
Subtract intercalary remainder from rule years; each time the remainder fills the intercalation factor you gain one month; count from civil new year (outside the count) to locate the leap month. Leap placement may shift; the rule is that a month without a mid-climate is intercalary. Procedure to compute the twenty-four qi:
14
滿
Take years since upper origin (outside the count), multiply by remainder number, divide by era factor for accumulated days; the remainder is fractional day remainder. Subtract sixty-day cycles from accumulated days; the remainder is greater remainder. Name greater remainder from jiazi (outside the count) for the winter solstice of civil month 11. To find the next qi:
15
滿滿
Add 15 to greater remainder, 8,626 to small remainder, and 5 to small parts. When small parts reach 6, carry to small remainder; when small remainder fills era factor, carry to greater remainder; name as before for the next qi. To find the earth phase (tu wang) period:
16
Add 27 to winter-solstice greater remainder and 15,528 to small remainder for the late-winter earth tenure day. Add again 91 to greater remainder and 12,270 to small remainder for the next earth tenure day. Procedure for computing submergence (mo):
17
滿
Multiply winter-solstice fractional remainder by 90, subtract from submergence parts; divide by submergence factor for days; the remainder is day remainder; count from winter solstice (outside the count) for the submergence day. To find the next submergence:
18
滿
Add 69 days and 34,442 to day remainder; when remainder fills submergence factor, carry to days for the next submergence. When day remainder is exhausted, the cycle ends (mie). Procedure for the sun's daily lodge:
19
滿 宿
Multiply new-moon accumulated days by era factor for degree dividend; subtract circumference of heaven; quotient by era factor gives accumulated degrees; remainder is degree remainder. Name from lodge Void I, subtract successive lodges (outside the count) for the sun's lodge at midnight on month-11 new moon. To find the next month:
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Add 30 degrees for a long month, 29 for a short month; when entering Void, subtract degree parts. To find motion parts:
21
滿滿
Divide degree remainder by small-part factor for motion parts; the remainder is small parts; carry when parts fill their factors. For the next day: add one degree. On entering Void, subtract 6 motion parts and 147 small parts.
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Procedure for the moon's lodge:
23
滿滿
Multiply new-moon fractional remainder by 124 for degree remainder and by 860 for minute parts; carry minute parts into degree remainder, then degree remainder into degrees by era factor. Subtract this from the new-moon midnight solar position to obtain the moon's lodge. To find the next month:
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Long month: add 35 degrees plus the listed remainders and minute parts; short month: add 22 degrees plus its listed parts; on entering Void, subtract degrees.
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522524
Slow-Fast (chi ji) sequence: (See tables on pp. 522–524 of the source edition.)〉 Procedure to enter the Slow-Fast sequence:
26
滿
Multiply new-moon accumulated days by communication factor for communication dividend; subtract communication cycle; divide by communication factor for days; remainder is day remainder. Name the day (outside the count) for midnight entry into the sequence on month-11 new moon. To find the next month:
27
滿
Long month: add 2 days; short month: add 1 day; day remainder always 11,746. When the sequence reaches 27 days with day remainder 14,631, drop that cycle. For the next day: add one day. To find the sun's true (fixed) daily lodge:
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滿 滿退
Multiply midnight sequence day remainder by the adjustment rate, apply surplus-deficit to accumulated parts, scale by difference rate; divide by era factor for degrees; add surplus or subtract deficit from mean solar degree for true position. If increase overflows the factor or decrease underflows, adjust by one era factor. Find degree motion parts by the same method. For the next day, add according to whether the sequence entry is slow or fast. On entering Void, subtract parts as above.
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Yin-Yang sequence:
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Adjustment rates (decrease-increase)
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Plus 16
32
Plus 15
33
Plus 14
34
31
35
Plus 12
36
45
37
57
38
66
39
71
40
72
41
64
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Day 11
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Minus 13
44
54
45
Day 12
46
Minus 15
47
41
48
Day 13
49
Minus 16
50
26
51
Day 14
52
Minus 16
53
滿滿
To enter the Yin-Yang sequence: take communication dividend, subtract conjunction cycle; remainder under conjunction number 358,888.5 is yang-sequence entry for the new moon; subtract each portion for yin entry; divide by communication factor for days; remainder is day remainder. Name the day (outside the count) for midnight sequence entry on month-11 new moon.
54
滿
To find the next month: Long month: add 2 days; short month: add 1 day; day remainder always 20,779. When the sequence reaches 13 days with day remainder 15,987.5, drop that cycle. At yang's end one enters yin; at yin's end one enters yang.
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滿 滿滿
For the next day: add one day. For new/full moon correction: multiply new-moon fractional remainder by 2,029; divide by 303 for day remainder; double the remainder for small parts to get new-moon difference. Add 14 days, day remainder 21,186, and small parts 125. When small parts reach 606, carry to day remainder; when day remainder fills communication factor, convert to days for full-moon difference.
56
滿滿滿
Add again for the following new moon. For conjunction and eclipse: take midnight yin-yang sequence entry and remainder at new/full moon, drop halves, set small parts 303, and add the difference number. Carry small parts into day remainder and day remainder into days; when days complete one sequence, subtract the cycle. Name the day (outside the count) for sequence entry at the instant of new or full moon.
57
滿 滿退
If hour-entry is 1 day with remainder ≤4,198 and small parts ≤428, or 12 days with remainder ≥11,788 and small parts ≥481, new moon yields conjunction and full moon yields eclipse. For fixed remainders at conjunction/eclipse: add difference day remainder to midnight slow-fast remainder; carry into days when remainder fills communication factor. Multiply sequence remainder by adjustment rate, adjust surplus-deficit parts, scale by difference factor, then subtract surplus or add deficit from base new/full fractional remainder.
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滿 滿 滿
On overflow or underflow in adjustment, carry or borrow using the day factor. For event hour: multiply fixed fractional remainder by 12, divide by day factor for double-hours; count from zi (outside the count). If remainder remains, multiply by four; each day-factor quotient gives minor (shao), half (ban), or major (tai) subdivisions. Further remainder: multiply by three; quotients are strong (qiang); combine with prior subdivisions for compound labels.
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Two quotients yield minor-weak; combine upward through half-weak and major-weak to a full weak double-hour named from the prior hour. For lunar latitude: take yin-yang sequence remainder, multiply by adjustment rate, divide by communication factor, and adjust the combined number. Divide the fixed number by twelve for degrees. The remainder in quarters yields minor, half, and major subdivisions. Further remainder in thirds: one gives strong, two minor-weak, completing lunar distance from the ecliptic.
60
529531
Yang sequence is outside the path; yin sequence inside. (See tables on pp. 529–531 of the source edition.)〉 For dusk, dawn, and culmination stars, apply the same degrees as at midnight solar position. Procedure to compute the five planets:
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Jupiter rate (mu lu): 15,753,082. Mars rate (huo lu): 30,804,196. Saturn rate (tu lu): 14,930,354. Venus rate (jin lu): 23,060,014.
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Mercury rate (shui lu): 4,576,204.
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For each planet: take degree dividend, subtract its rate repeatedly; treat the remainder over era factor as days since civil new-year new moon (outside the count) for conjunction day.
64
滿滿
For conjunction degree: add year-entry days and remainder to new-year solar accumulated degrees; carry at era factor; drop full circles; name from Void I (outside the count).
65
滿
For first visibility: add tabulated morning/evening concealment days and remainder to conjunction; carry remainder into days; name as before.
66
滿
For appearance degree: add concealment degrees and remainder to conjunction position; carry; subtract on entering Void; name as before.
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滿
Planetary motion: convert degree remainder to motion and small parts; add daily motion; carry at factor; hold in station, subtract in retrograde; concealment may leave degrees unused. On direct motion entering Void, subtract 6 motion parts and 147 small parts; add them when retrograde leaves Void.
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Jupiter:
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退 西
First conjunction with the sun: 16 days concealed (remainder 17,832), motion 2 degrees (remainder 37,504), then morning visibility in the east. Prograde at four parts per day; in 112 days advances 19 degrees 11 parts. Stationary for 28 days. Retrograde at three parts per day; in 86 days retreats 11 degrees 5 parts. Stationary again for 28 days. Prograde at four parts per day; after 112 days, evening concealment in the west with initial day and degree remainders. One synodic cycle: 398 days (remainder 35,564), motion 33 degrees (remainder 25,215).
70
Mars:
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退 西
First conjunction: 72 days concealed (remainder 608), motion 55 degrees (remainder 28,865), morning visibility east. Prograde fast: seventeen parts per day; 92 days, 68 degrees. Slightly slow: fourteen parts per day; 92 days, 56 degrees. Very slow: nine parts per day; 92 days, 36 degrees. Stationary 10 days. Retrograde six parts per day; 64 days, retreat 16 degrees 16 parts. Stationary again 10 days. Prograde slow: nine parts per day for 92 days. Slightly fast: fourteen parts per day for 92 days. Very fast: seventeen parts per day for 92 days. Evening concealment in the west; day and degree remainders as at first. One cycle: 780 days (remainder 1,216), motion 414 degrees (remainder 30,258); subtract one circuit; net motion 49 degrees (remainder 19,809).
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Saturn:
73
退 西
First conjunction: 17 days concealed (remainder 1,378), 1 degree motion (remainder 19,333), morning east; then direct at two parts per day, 84 days for 7 degrees 7 parts. Stationary 33 days. Retrograde one part per day; 110 days, retreat 4 degrees 18 parts. Stationary again 33 days. Prograde two parts per day for 84 days; evening concealment west with initial remainders. One cycle: 378 days (remainder 2,756), motion 12 degrees (remainder 31,798).
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Venus:
75
西 退西 退 退
First conjunction: 39 days concealed (remainder 38,126), motion 49 degrees (same remainder), evening visibility west. Prograde fast: 1 degree 5 parts per day; 92 days, 112 degrees. Slightly slow: 1 degree 4 parts per day; 92 days, 108 degrees. Very slow: seventeen parts per day; 45 days, 33 degrees 6 parts. Stationary 9 days. Slow retrograde: sixteen parts per day; 9 days, retreat 6 degrees 6 parts; evening concealment west. Concealed 5 days, retreat 5 degrees, then conjunction with the sun. Another 5 days retreat 5 degrees, morning east; retrograde sixteen parts per day for 9 days; stationary 9 days. Prograde slow: seventeen parts per day for 45 days. Slightly fast: 1 degree 4 parts per day for 92 days. Very fast: 1 degree 5 parts per day for 92 days. Morning concealment east; day and degree remainders as at first. One cycle: 583 days (remainder 36,761); planetary motion matches. Subtract one circuit; net motion 218 degrees (remainder 26,313). Conjunction half-cycle: 291 days (remainder 38,126); motion likewise.
76
Mercury:
77
西 退西 退 退
First conjunction: 14 days concealed (remainder 37,115), motion 30 degrees (same remainder), evening west. Prograde fast: 1 degree 6 parts per day, 23 days for 29 degrees; slow: twenty parts per day, 8 days for 6 degrees 22 parts. Stationary 2 days. Slow: eleven parts per day; 2 days, retreat 22 parts; evening concealment west. Concealed 8 days, retreat 8 degrees, then conjunction. Another 8 days retreat 8 degrees, then morning visibility east. Retrograde eleven parts per day for 2 days. Stationary 2 days. Fast: 1 degree 6 parts per day for 23 days. Morning concealment east; day and degree remainders as at first. One cycle: 115 days (remainder 34,739); motion matches. One conjunction: 57 days (remainder 37,115); motion likewise. At upper-origin year jiazi: civil new year jiazi new moon, winter solstice at midnight; sun, moon, and five planets at the start of Void; yin-yang and slow-fast sequences also begin here.
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At upper-origin year jiazi: civil new year jiazi new moon, winter solstice at midnight; sun, moon, and five planets at the start of Void; yin-yang and slow-fast sequences also begin here.
79
Liang Tianjian year 3: Zu Chongzhi's son Heng memorialized that He Chengtian's calendar was erroneous and unusable. In year 9, month 1, an edict adopted Zu Chongzhi's Jiazi Epoch Calendar for issuing the new moon. Chen continued Liang practice and used Chongzhi's calendar. Under Liao, Emperor Shengzong adopted Jia Jun's new calendar while retaining the Song name Great Brightness. Jin titled it the Revised Great Brightness Calendar. In the Yuan it was likewise the Revised Great Brightness Calendar. After the Season-Granting Calendar replaced it, a Directorate of Astronomy kept the old methods, revised at each jiazi winter solstice. The text remained in the Grand Astrologer's archive, barred from circulation.
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